[XCore] Convert a couple of tests to FileCheck.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179619 91177308-0d34-0410-b5e6-96231b3b80d8
[XCore] Give test more generic name.
    
I intend to extend the test with more offset folding checks


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179620 91177308-0d34-0410-b5e6-96231b3b80d8