Refactor art::Dex2Oat::ParseArg.

Split up art::Dex2Oat::ParseArg to allow
`clang++ -01 -Werror -Wframe-larger-than=1728` to compile
dex2oat.cc.

Change-Id: I0b45f394568765ccd849c87a7cf910507291e65d
1 file changed