Fix WASM restore failing with runtime pack missing

[ilonatommy]

This should fix perf tests failures in runtime, e.g dotnet/runtime#124134.

When running WASM benchmarks, the build fails with error NETSDK1112:
"The runtime pack for Microsoft.NETCore.App.Runtime.browser-wasm was not downloaded."

BenchmarkDotNet runs:

# restore that works for portable packages only
dotnet restore

# build without restore, when the project has `<RuntimeIdentifier>browser-wasm</RuntimeIdentifier>`, build fails because the runtime pack was not downloaded
dotnet build --no-restore

Runtime restore must be explicitly specified on the command line.
This change adds -r browser-wasm to the restore command when the runtime is WasmRuntime.

log

[2026/02/08 01:19:45][INFO] // start /datadisks/disk1/work/B6C309DE/p/dotnet/dotnet  build "/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/BenchmarkDotNet.Autogenerated.csproj" -f net11.0 -c Release --no-restore --nodeReuse:false /p:UseSharedCompilation=false /p:Deterministic=true /p:Optimize=true /p:NuGetPackageRoot="/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/packages" -bl:MicroBenchmarks-Wasm-1-build-no-restore.binlog /p:ArtifactsPath="/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/" /p:OutDir="/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/bin/Release/net11.0/browser-wasm/" /p:OutputPath="/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/bin/Release/net11.0/browser-wasm/" /p:PublishDir="/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/publish/" --output "/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/bin/Release/net11.0/browser-wasm/" in /datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1
[2026/02/08 01:19:46][INFO] /datadisks/disk1/work/B6C309DE/p/dotnet/sdk/11.0.100-preview.1.26069.103/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(546,5): error NETSDK1112: The runtime pack for Microsoft.NETCore.App.Runtime.browser-wasm was not downloaded. Try running a NuGet restore with the RuntimeIdentifier 'browser-wasm'. [/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/BenchmarkDotNet.Autogenerated.csproj::TargetFramework=net11.0]
[2026/02/08 01:19:46][INFO] Build FAILED.
[2026/02/08 01:19:46][INFO] /datadisks/disk1/work/B6C309DE/p/dotnet/sdk/11.0.100-preview.1.26069.103/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(546,5): error NETSDK1112: The runtime pack for Microsoft.NETCore.App.Runtime.browser-wasm was not downloaded. Try running a NuGet restore with the RuntimeIdentifier 'browser-wasm'. [/datadisks/disk1/work/B6C309DE/w/C16D0A77/e/performance/artifacts/bin/for-running/MicroBenchmarks/MicroBenchmarks-Wasm-1/BenchmarkDotNet.Autogenerated.csproj::TargetFramework=net11.0]

[radekdoulik]

LGTM

[adamsitnik]

LGTM,