Linker: Update -override testcase to check callers

Check that `@main` is calling `@foo2` (the renamed internal function),
not the `@foo` with external linkage that's been pulled in from the
override file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235730 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed