[1.8>1.9] [MERGE #4647 @agarwal-sandeep] OS#15659337: Try to allocate JIT code in PreReservedSegment even if CFG is not enabled
[1.8>1.9] [MERGE #4647 @agarwal-sandeep] OS#15659337: Try to allocate JIT code in PreReservedSegment even if CFG is not enabled

Merge pull request #4647 from agarwal-sandeep:vso15659337

This speeds up stack walking IsNativeAddress checks when CFG is not enabled.

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