LTO: Replace InputFile::Symbol::getFlags() with predicate accessors. NFC.

This makes the predicates independent of the flag representation
and makes the code a little easier to read.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298951 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed