Add browser WASM R2R test leg

[jkotas]

Goal

Restore the browser-wasm ReadyToRun runtime-test leg introduced by #133134 and temporarily removed by #133294.

Re-enable criteria

• Temporarily remove the failing R2R_CG2 leg (Disable browser WASM R2R test leg #133294).
• Every failure from a fresh clean-main rolling run is fixed or narrowly disabled against an open issue.
• Skips preserve interpreter and unaffected-platform coverage.
• A fresh rolling browser-wasm R2R run completes without untracked failures.
• Restore the deleted R2R_CG2 matrix entry.

Open failure tracking

Failure	Tracking issue	Fix PR	Status
portableEntryPoint assertion in Runtime_79354	#131886	-	Open
Wasm function signatures exceeding the 1,000-parameter engine limit	#132855	#132865	Fix PR open
OBJECTREF accessed in preemptive GC mode	#133219	#133269	Draft fix PR
Frame::Pop / frames popped out of order	#133221	-	Open
wasmAbiType != CORINFO_WASM_TYPE_VOID in LowerStoreSingleRegCallStruct	#133224	#133281	Fix PR open
Browser-incompatible Regression_o_2 tests (Assembly.Location and kernel32)	#133259	#133274	Draft fix PR
fFrameWasUnwound followed by a cyclic InlinedCallFrame dump in JIT/opt/OSR/pinnedlocal	#133286	-	Open; observed on #133276, exact-main baseline still needed
Crossgen2 cannot load TypeMapApp while compiling Interop/Interop/TypeMapBlobOnlyLib.dll	#133303	-	Open
Generic multidimensional array access traps with null function or function signature mismatch	#133307	-	Open; related to closed #129821 / #129825

#131925 is an older related tracker for the preemptive-mode OBJECTREF assertion family. #133219 is the tracker for the failures exposed by this lane.

Completed fixes

Failure	Tracking issue	Fix
QCall exception marshalling failures	#132022	#132420
Invalid wasm from narrowed multi-use operands	#133209 and #133255	#133210
Managed wasm virtual IPs misclassified during funclet stack walks	#133264	#133266

Still to classify

The original lane census and subsequent same-base CI comparisons contain failure shapes without a confirmed open tracker:

• exceptionhandling.cpp:4273 ExInfo collision in Regression_6
• memory access out of bounds in Regression_3 (local reproduction diverges)
• null function or signature mismatch in Directed_ro, Loader, and Methodical work items
• conditional false-edge fallthrough across a wasm Try end in throwinfinally_50

The Interop and readytorun failures reproduced in both #133276 and #133281 CI builds against the same main base (de29e26a4f69), so they are not regressions caused by #133281.

These should receive a tracking issue or be shown to be covered by an existing issue before the lane is restored.

Note

This tracking update was generated with GitHub Copilot.

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[lewing]

The helix queue monitor is delaying obvious visible reporting of failing legs until everything has completed which is causing some over aggressive merging on "yellow". That is what happened here but there are several other recent instances. I have a prospective Build Insights PR open and I'm engaging with the services side to try surface failures sooner on the pr status.

There are several open issues and prs in flight to fix the failures here and I will add tracking info once I've categorized them all. Given the rate of churn in the wasm r2r tests enabling this again is a high priority.