Pass alignment when using GCC_C_FE_VERSION_2

When the GCC compiler plugin responds with GCC_C_FE_VERSION_2, gdb can
use the new 'finish_record_with_alignment' method.  This lets gdb pass
alignment information to the compiler, which in turn fixes the test
case included in this patch.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31397


3 files changed