[PECOFF] Give a better name to the linker generated file.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@194847 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF] Remove unnecessary static member.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@194851 91177308-0d34-0410-b5e6-96231b3b80d8