Regression (240345@main): Many ChakraCore.yaml JSC tests are flaky failures on jsc-mips queue

• Component: JavaScriptCore
• Status: NEW ---

[Aakash Jain]

Many ChakraCore.yaml JSC tests are flaky failures.

e.g.:
https://ews-build.webkit.org/#/builders/45/builds/6414

Found 149 pre-existing JSC test failures: 
ChakraCore.yaml/ChakraCore/test/Function/argumentsResolution.js.default,
ChakraCore.yaml/ChakraCore/test/Operators/unaryOps.js.default,
stress/for-in-tests.js.default,
ChakraCore.yaml/ChakraCore/test/es6/unicode_whitespace.js.default,
ChakraCore.yaml/ChakraCore/test/UnifiedRegex/class-case.js.default,
stress/for-in-modify-int-loop-var.js.eager-jettison-no-cjit,
stress/has-own-property-structure-for-in-loop-correctness.js.no-llint,
stress/for-in-invalidate-context-weird-assignments.js.no-cjit-collect-continuously,
stress/sloppy-mode-function-hoisting.js.no-cjit-collect-continuously,
microbenchmarks/sorting-benchmark.js.mini-mode ... 

Found flaky tests: 
ChakraCore.yaml/ChakraCore/test/Bugs/blue_1096569.js.default,
ChakraCore.yaml/ChakraCore/test/Error/CallNonFunction.js.default,
ChakraCore.yaml/ChakraCore/test/Error/ErrorCtorProps.js.default,
ChakraCore.yaml/ChakraCore/test/Function/argumentsResolution.js.default,
ChakraCore.yaml/ChakraCore/test/Object/defineProperty.js.default,
ChakraCore.yaml/ChakraCore/test/Operators/unaryOps.js.default,
ChakraCore.yaml/ChakraCore/test/UnifiedRegex/class-case.js.default,
ChakraCore.yaml/ChakraCore/test/es5/enumerable.js.default,
ChakraCore.yaml/ChakraCore/test/es5/hasItem.js.default,
ChakraCore.yaml/ChakraCore/test/es6/unicode_whitespace.js.default


Other examples:
https://ews-build.webkit.org/#/builders/45/builds/6427
https://ews-build.webkit.org/#/builders/45/builds/6375
https://ews-build.webkit.org/#/builders/45/builds/6320

[Aakash Jain]

Results database points to regressions range of 240344@main - 240347@main for https://results.webkit.org/?suite=javascriptcore-tests&test=ChakraCore.yaml%2FChakraCore%2Ftest%2FBugs%2Fblue_1096569.js.default  

r280760 (240345@main) seems like the one which caused this, corresponding bug was https://bugs.webkit.org/show_bug.cgi?id=227989. On this bug jsc-mips-tests EWS didn't run on latest patch, but did indicate similar failures on previous patch in https://ews-build.webkit.org/#/builders/45/builds/6089