[PowerPC] Attempt to fix fast-isel-i64offset.ll failure

The test case added in r265023 is failing on ninja-x64-msvc-RA-centos6.
Update the test to make less specific assumptions on code generation.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265026 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed