[main] Source code updates from dotnet/runtime

[dotnet-maestro]

Note

This is a codeflow update. It may contain both source code changes from
the source repo
as well as dependency updates. Learn more here.

This pull request brings the following source code changes

From https://github.com/dotnet/runtime

• Subscription: 6458ae35-db00-43d0-af59-e57a01ca3120
• Build: 20260917.17 (332646)
• Date Produced: September 18, 2026 2:39:21 AM UTC
• Commit: 09b90456ffa261e50233034d6214f805587e2c05
• Commit Diff: 8970fe8...09b9045
• Branch: main

Diff the source with this PR branch

darc vmr diff --name-only https://github.com/dotnet/runtime:09b90456ffa261e50233034d6214f805587e2c05..https://github.com/dotnet/dotnet:darc-main-12ef7faf-9a10-4a43-beae-bdc333654e72

[dotnet-maestro]

Note

PRs from original repository included in this codeflow update:

• Fix Wasm R2R exceptions escaping filters runtime#133932
• Unify native API availability probes runtime#134073
• [PERF] Enable slow performance CI for mainline releases runtime#134104
• Abort when there's an attempt to reinitialize a runtime thread object runtime#132448
• Avoid duplicate ValueTask checks in transparent awaits runtime#133023
• Check the IValueTaskSource case first in HandleSuspended runtime#133076
• JIT: Enable async inlining stress under JitStress runtime#132517
• JIT: preserve side effect ordering when unrolling UTF16 comparisons runtime#134099
• Add Microsoft.Extensions.FileProviders.Composite package README runtime#133654
• [wasm][coreclr] ReadyToRun for CoreCLR browser-wasm runtime#133378
• [iOS] Avoid debugger patches in R2R code without dynamic code support runtime#133577
• Implement IParsable on Uri runtime#134112
• Fix TimeSpan constructor overflow runtime#134113
• Fix .NET 11 rc1 SDK crash on RHEL8 arm64 runtime#133887
• JIT: Fix null-check ordering in EH regions runtime#133827
• [wasm] Package CoreCLR native symbol map runtime#134010
• JIT: stop tail duplication from looping forever around a conditional … runtime#134097
• JIT: Preserve overflow checks when folding scaled indexes runtime#133802
• Fix null-forgiving operator misuse in System.Diagnostics.EventLog runtime#126639
• [perf] Optimise {ActivityTraceId|ActivitySpanId}.CopyTo() runtime#134135
• Make analyzers and ILLink trimming opt-in via MSBuild properties runtime#123292
• Fix ILTrim field store dataflow runtime#134079
• Fix XARCH importation of isPositive and isNegative runtime#134151

💡 You may consult the FAQ for more information or tag @dotnet/prodconsvcs for assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
1 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[maestro-approver]

This pull request contains only source updates from https://github.com/dotnet/runtime.

• Commit Diff: 8970fe8...09b9045