PR14573: Unnamed parameters in debug info, Part 2

Catch some cases I'd missed in r171605 related to unnamed parameters of record
type. This resolves all remaining cases of PR14573 suppression in the GDB 7.5
test suite. Fix to the test suite to follow.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171633 91177308-0d34-0410-b5e6-96231b3b80d8