[gdb/testsuite] Run two test-cases with ASAN_OPTIONS=verify_asan_link_order=0

[gdb/testsuite] Run two test-cases with ASAN_OPTIONS=verify_asan_link_order=0

When building gdb with -fsanitize=address we run into:
...
builtin_spawn gdb -nw -nx -iex set height 0 -iex set width 0 -data-directory \
  build/gdb/data-directory^M
==10637==ASan runtime does not come first in initial library list; you \
  should either link runtime to your application or manually preload it with \
  LD_PRELOAD.^M
ERROR: GDB process no longer exists
...

Prevent the ASan runtime error by using
ASAN_OPTIONS=verify_asan_link_order=0.  This makes both test-cases pass.

Tested on x86_64-linux.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29358