Assertion failed 'this->bbNext->isEmpty()'

[BruceForstall]

All jitstress jobs are failing:

https://dev.azure.com/dnceng/public/_build/results?buildId=1089760&view=ms.vss-test-web.build-test-results-tab&runId=33410616&resultId=103827&paneView=dotnet-dnceng.dnceng-build-release-tasks.helix-test-information-tab

    JIT\Methodical\flowgraph\bug619534\twoEndFinallys_il\twoEndFinallys_il.cmd [FAIL]
      
      Assert failure(PID 1332 [0x00000534], Thread: 4256 [0x10a0]): Assertion failed 'this->bbNext->isEmpty()' in 'Test:TwoEndFinallys(System.String[]):Test' during 'SSA: insert phis' (IL size 137)
      
          File: D:\workspace\_work\1\s\src\coreclr\jit\block.cpp Line: 1539
          Image: C:\h\w\9A55085C\p\corerun.exe
      
      
      Return code:      1
      Raw output file:      C:\h\w\9A55085C\w\B3B40983\e\JIT\Methodical\Reports\JIT.Methodical\flowgraph\bug619534\twoEndFinallys_il\twoEndFinallys_il.output.txt
      Raw output:
      BEGIN EXECUTION
       "C:\h\w\9A55085C\p\corerun.exe" twoEndFinallys_il.dll 
      Expected: 100
      Actual: -1073740286
      END EXECUTION - FAILED

[BruceForstall]

It appears this is due to #50806

[BruceForstall]

@AndyAyersMS Given this is failing in all jitstress configurations, can you revert #50806?

[AndyAyersMS]

Let me take a quick look. Might be just as easy to fix.

[AndyAyersMS]

Fix looks simple enough: BasicBlock::isEmpty isn't checking for PHIs properly. Testing....