[Inliner] Modernize all of the inliner tests that were using grep.

This mostly involved converting from grep to FileCheck and tidying up
the IR used.

In one case (invoke_test-3.ll) the test had become completely pointless
as we use 'resume' rather than 'unwind' now, and even then it did not
occur at the end of the line.

llvm-svn: 290570