Skip Iri_UnicodePlane3_13 test on 32-bit platforms to prevent OOM

[Copilot]

Description

The Iri_UnicodePlane3_13 test fails with OutOfMemoryException on 32-bit platforms. The test processes Unicode planes 3-13 (0x30000-0xDFFFF), creating a string of 720,895 characters that allocates several hundred MB—exceeding 32-bit addressable memory limits.

Changes

• Changed [Fact] to [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.Is64BitProcess))] for Iri_UnicodePlane3_13 test
• Test now skips on 32-bit processes, runs on 64-bit as before

Other Unicode plane tests (0-2, 14, 15-16) process only single planes (~65K characters each) and remain unaffected.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Test failure: System.PrivateUri.Tests.IriTest.Iri_UnicodePlane3_13</issue_title>
<issue_description>Failed in: runtime-coreclr libraries-jitstress 20260212.1

Failed tests:

net11.0-windows-Release-x86-jitstress2-Windows.10.Amd64.Open
- System.PrivateUri.Tests.IriTest.Iri_UnicodePlane3_13

Error message:

System.OutOfMemoryException : Exception of type 'System.OutOfMemoryException' was thrown.

Stack trace:

   at System.GC.<AllocateUninitializedArray>g__AllocateNewArrayWorker|77_0[T](Int32 length, Boolean pinned) in /_/src/coreclr/System.Private.CoreLib/src/System/GC.CoreCLR.cs:line 831
   at System.Buffers.SharedArrayPool`1.Rent(Int32 minimumLength) in /_/src/libraries/System.Private.CoreLib/src/System/Buffers/SharedArrayPool.cs:line 107
   at System.Text.ValueStringBuilder.Grow(Int32 additionalCapacityBeyondPos) in /_/src/libraries/Common/src/System/Text/ValueStringBuilder.cs:line 265
   at System.UriHelper.EscapeStringToBuilder(ReadOnlySpan`1 stringToEscape, ValueStringBuilder& vsb, SearchValues`1 noEscape, Boolean checkExistingEscaped) in /_/src/libraries/System.Private.Uri/src/System/UriHelper.cs:line 276
   at System.Uri.GetCanonicalPath(ValueStringBuilder& dest, UriFormat formatAs) in /_/src/libraries/System.Private.Uri/src/System/Uri.cs:line 4202
   at System.Uri.RecreateParts(ValueStringBuilder& dest, String str, UriComponents parts, UInt16 nonCanonical, UriFormat formatAs) in /_/src/libraries/System.Private.Uri/src/System/Uri.cs:line 2893
   at System.Uri.RecreateParts(UriComponents parts, UInt16 nonCanonical, UriFormat formatAs) in /_/src/libraries/System.Private.Uri/src/System/Uri.cs:line 2729
   at System.Uri.GetEscapedParts(UriComponents uriParts) in /_/src/libraries/System.Private.Uri/src/System/Uri.cs:line 2681
   at System.Uri.GetComponentsHelper(UriComponents uriComponents, UriFormat uriFormat) in /_/src/libraries/System.Private.Uri/src/System/UriExt.cs:line 869
   at System.Uri.InternalGetComponents(UriComponents components, UriFormat format) in /_/src/libraries/System.Private.Uri/src/System/UriExt.cs:line 317
   at System.Uri.get_AbsoluteUri() in /_/src/libraries/System.Private.Uri/src/System/Uri.cs:line 777
   at System.PrivateUri.Tests.IriTest.EscapeUnescapeTestComponent(String uriInput, UriComponents component) in /_/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs:line 383
   at System.PrivateUri.Tests.IriTest.VerifyUriNormalizationForEscapedCharacters(String uriInput) in /_/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs:line 311
   at System.PrivateUri.Tests.IriTest.Iri_UnicodePlane3_13() in /_/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs:line 244
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args) in /_/src/coreclr/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.CoreCLR.cs:line 36
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr) in /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs:line 57
```</issue_description>

<agent_instructions>Disable this specific test when running on 32bit as it can allocate a few hundred MB of memory</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Test failure: System.PrivateUri.Tests.IriTest.Iri_UnicodePlane3_13 #124417

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[vcsjones]

"Is 64-bit" is not really a good proxy for "has a lot of memory" anymore. Mobile devices (Android / iOS) are 64-bit but tend to be memory constrained anyway. See RunGetBitLengthTestsLarge as another such example.

Consider marking this OuterLoop as well.