[ORC] Tidy up JITSymbolFlags to remove the need for some explicit static_casts.

Removes the implicit conversion to the underlying type for
JITSymbolFlags::FlagNames and replaces it with some bitwise and comparison
operators.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341282 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed