[PATCH][gdb/testsuite] Allow override of ASAN_OPTIONS in lib/gdb.exp

[Tom Tromey]

>>>>> "Tom" == Tom de Vries via Gdb-patches <gdb-patches@sourceware.org> writes:

Tom> Use set_sanitizer_default for ASAN_OPTIONS in lib/gdb.exp.

[...]
Tom> Any comments?

Seems fine to me.  Thank you.

Tom