asan-dg.exp (asan_get_gtest_test_list, [...]): New procedures.
* lib/asan-dg.exp (asan_get_gtest_test_list,
asan_get_gtest_expect_death_list, asan-gtest): New procedures.
(proc ${tool}_load): Remember [asan_get_gtest_test_list "$output"]
and [asan_get_gtest_expect_death_list "$output"] in global vars.
(asan_symbolize): Sanitize [] characters from key.
* g++.dg/asan/asan_test_config.h: New file.
* g++.dg/asan/asan_globals_test.cc: New file.
* g++.dg/asan/asan_test_utils.h: New file.
* g++.dg/asan/dejagnu-gtest.h: New file.
* g++.dg/asan/asan_test.cc: New file.
* g++.dg/asan/asan_test.C: New test.