Misc test cleanups.

* tbaa-struct.cpp always has a 64 bit pointer.
* f32:32:32, f64:64:64 and f128:128:128 are defaults, don't assume they are
  printed.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197415 91177308-0d34-0410-b5e6-96231b3b80d8