[LinkerScript] OUTPUT_FORMAT: Parse Quoted Strings

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@202111 91177308-0d34-0410-b5e6-96231b3b80d8
[COFF] Refactor .drectve section handling. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@202113 91177308-0d34-0410-b5e6-96231b3b80d8