Fix typo in size remarks for module passes

Fix typo in size remarks for module passes

ModuleCount = InstrCount was incorrect. It should have been
InstrCount = ModuleCount. This was making it emit an extra, incorrect remark
for Print Module IR.

The test didn't catch this, because it didn't ensure that the only remark
output was from the desired pass. So, it was possible to have an extra remark
come through and not fail. Updated the test so that we ensure that the last
remark that's output comes from the desired pass. This is done by ensuring
that whatever is being read after the last remark is YAML output rather than
some incorrect garbage.

llvm-svn: 341267