[MERGE #4125 @aaronsgiles] ARM64: Clean up some EH-related assembly code.
[MERGE #4125 @aaronsgiles] ARM64: Clean up some EH-related assembly code.

Merge pull request #4125 from aaronsgiles:user/aarongi/work3

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