[llvm-readobj] Weaken a check in the test added by r354567

The check includes a substring, configurable by PACKAGE_NAME in CMake.
This leads to failures if PACKAGE_NAME is not the default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354586 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed