allow optional signext attribute

Allow the tests to succeed with tne signext (or other) attribute is present.  The attributes
show up for Power, but not for x86*, so need to be appropriately wildcarded.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210050 91177308-0d34-0410-b5e6-96231b3b80d8