Object, COFF: Clean up formatting in hasExtendedRelocations

No functionality changed intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221867 91177308-0d34-0410-b5e6-96231b3b80d8
Object, COFF: Fix some theoretical bugs

getObject didn't consider the case where a pointer came before the start
of the object file.  No test is included, trying to come up with
something reasonable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221868 91177308-0d34-0410-b5e6-96231b3b80d8
Object, COFF: Cleanup some code in getSectionName

Use StringRef::startswith to tidy up some code, no functionality change
intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221869 91177308-0d34-0410-b5e6-96231b3b80d8
Object, COFF: getRelocationSymbol shouldn't assert

lib/Object is supposed to be robust to malformed object files.  Don't
assert if we don't have a symbol table.  I'll try to come up with a test
case later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221870 91177308-0d34-0410-b5e6-96231b3b80d8
llvm-readobj, COFF: Remove an unused variable

printRelocation doesn't use the section contents.  No functionality
change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221871 91177308-0d34-0410-b5e6-96231b3b80d8