Pass -fno-sanitize-recover=all to make all UBSan detections fatal

From the clang docs:

> By default, non-fatal checks are those enabled by UndefinedBehaviorSanitizer, except for -fsanitize=return and -fsanitize=unreachable.

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
  with:
  submodules: recursive
  - name: Build
- run: CMAKE_OPTIONS="-DCMAKE_C_FLAGS=-fsanitize=address,undefined" make
+ run: CMAKE_OPTIONS="-DCMAKE_C_FLAGS=-fsanitize=address,undefined -fno-sanitize-recover" make
  - name: Test
  run: make test
  - name: Test with Aggressive GC