[1.6>1.7] [MERGE #3346 @pleath] [OSG 9773504] Silence a noisy assert.
[1.6>1.7] [MERGE #3346 @pleath] [OSG 9773504] Silence a noisy assert.

Merge pull request #3346 from pleath:9773504

In source rundown mode, we're hitting an assert in byte code gen to the effect that we don't have a proper initial entry point on the function we're compiling. Make CleanupToReparse set an initial entry point before proceeding.

Microsoft/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore