System.Numerics.Tests.parseTest.RunParseToStringTests(culture: uk-UA) test failures

[jkotas]

This test runs as part of the libraries outer loop.

Hit in #119427. Log file: https://helixr1107v0xdcypoyl9e7f.blob.core.windows.net/dotnet-runtime-refs-pull-119427-merge-e179d39d041e4c21b3/System.Runtime.Numerics.Tests/1/console.8967a987.log?skoid=8eda00af-b5ec-4be9-b69b-0919a2338892&sktid=72f988bf-86f1-41af-91ab-2d7cd011db47&skt=2025-10-01T01%3A05%3A30Z&ske=2025-10-01T02%3A05%3A30Z&sks=b&skv=2024-11-04&sv=2024-11-04&st=2025-10-01T01%3A05%3A30Z&se=2025-10-01T02%3A05%3A30Z&sr=c&sp=r&sig=7IW6R8WrZP0cNbaHbzQaVlxd8lGUkdAbHB4%2BpInETpk%3D

    System.Numerics.Tests.parseTest.RunParseToStringTests(culture: uk-UA) [FAIL]
      System.FormatException : The value could not be parsed.
      Stack Trace:
        /_/src/libraries/System.Runtime.Numerics/src/System/Number.BigInteger.cs(29,0): at System.Number.ThrowOverflowOrFormatException(ParsingStatus status)
        /_/src/libraries/System.Runtime.Numerics/src/System/Number.BigInteger.cs(136,0): at System.Number.ParseBigInteger[TChar](ReadOnlySpan`1 value, NumberStyles style, NumberFormatInfo info)
        /_/src/libraries/System.Runtime.Numerics/src/System/Numerics/BigInteger.cs(707,0): at System.Numerics.BigInteger.Parse(ReadOnlySpan`1 utf8Text, NumberStyles style, IFormatProvider provider)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(828,0): at System.Numerics.Tests.parseTest.VerifyParseSpanToString(String num1, NumberStyles ns, Boolean failureNotExpected, String expected)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(884,0): at System.Numerics.Tests.parseTest.VerifyParseToString(String num1, NumberStyles ns, Boolean failureNotExpected, String expected)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(818,0): at System.Numerics.Tests.parseTest.VerifyParseToString(String num1, NumberStyles ns, Boolean failureNotExpected)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(689,0): at System.Numerics.Tests.parseTest.VerifyNumberStyles(NumberStyles ns, Random random)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(52,0): at System.Numerics.Tests.parseTest.RunParseToStringTests(CultureInfo culture)
           at InvokeStub_parseTest.RunParseToStringTests(Object, Span`1)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs(95,0): at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
    System.Numerics.Tests.parseTestThreshold.RunParseToStringTests(culture: uk-UA) [FAIL]
      System.FormatException : The value could not be parsed.
      Stack Trace:
        /_/src/libraries/System.Runtime.Numerics/src/System/Number.BigInteger.cs(29,0): at System.Number.ThrowOverflowOrFormatException(ParsingStatus status)
        /_/src/libraries/System.Runtime.Numerics/src/System/Number.BigInteger.cs(136,0): at System.Number.ParseBigInteger[TChar](ReadOnlySpan`1 value, NumberStyles style, NumberFormatInfo info)
        /_/src/libraries/System.Runtime.Numerics/src/System/Numerics/BigInteger.cs(707,0): at System.Numerics.BigInteger.Parse(ReadOnlySpan`1 utf8Text, NumberStyles style, IFormatProvider provider)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(828,0): at System.Numerics.Tests.parseTest.VerifyParseSpanToString(String num1, NumberStyles ns, Boolean failureNotExpected, String expected)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(884,0): at System.Numerics.Tests.parseTest.VerifyParseToString(String num1, NumberStyles ns, Boolean failureNotExpected, String expected)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(818,0): at System.Numerics.Tests.parseTest.VerifyParseToString(String num1, NumberStyles ns, Boolean failureNotExpected)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(689,0): at System.Numerics.Tests.parseTest.VerifyNumberStyles(NumberStyles ns, Random random)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(52,0): at System.Numerics.Tests.parseTest.RunParseToStringTests(CultureInfo culture)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(1349,0): at System.Numerics.Tests.parseTestThreshold.<>c__DisplayClass2_0.<RunParseToStringTests>b__1()
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/BigIntTools.cs(54,0): at BigIntTools.Utils.RunWithFakeThreshold(Int32& field, Int32 value, Action action)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(1347,0): at System.Numerics.Tests.parseTestThreshold.<>c__DisplayClass2_0.<RunParseToStringTests>b__0()
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/BigIntTools.cs(54,0): at BigIntTools.Utils.RunWithFakeThreshold(Int32& field, Int32 value, Action action)
        /_/src/libraries/System.Runtime.Numerics/tests/BigInteger/parse.cs(1346,0): at System.Numerics.Tests.parseTestThreshold.RunParseToStringTests(CultureInfo culture)
           at InvokeStub_parseTestThreshold.RunParseToStringTests(Object, Span`1)

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[artl93]

@eiriktsarpalis, @jkotas , I'm assessing a tool that identifies copilot readiness. I tried this offline, and I'm going to try it here if you don't mind.