[asan][test] Fix build errors in loongarch64

- Add get_bits_for_arch for loongarch64 detection, fix the following error,
```
$ make check-asan
-- sanitizer_common tests on "Linux" will run against "asan"
CMake Error at test/asan/CMakeLists.txt:22 (message):
  Unknown target architecture: loongarch64
Call Stack (most recent call first):
  test/asan/CMakeLists.txt:49 (get_bits_for_arch)
```

- Do not use __builtin_longjmp, fix the following error,
```
llvm-project/compiler-rt/lib/asan/tests/asan_test.cpp:635:3: error: __builtin_longjmp is not supported for the current target
  __builtin_longjmp((void**)buf, 1);
```

Differential Revision: https://reviews.llvm.org/D137012