Design: V8 Build Flag Consistency

[Dan Elphick]

Hi all,

This is an attempt to solve the problem of mismatching -Dflags used between compiling V8 and embedding it, which has frequently resulted in hard-to-understand failures.

https://docs.google.com/document/d/1yC5QaXzdruwK5Iz4YtNLMVuP8bi_kcicLsaehWDxtRw/edit?usp=sharing

Thanks,

Dan