Previously this was listed as a suppression, but we actually want this
permanently unsanitized. This should be faster and more reliable since
TASN won't have to match against symbolicated backtraces.

The ASAN poison functions was always defined in gc.c, even if ASAN was not
enabled. This made function calls to happen all the time even if ASAN is
not enabled. This commit defines these functions as empty macros when ASAN
is not enabled.

The content depends on ruby internal, not responsibility of the
caller.  Revive `RUBY_GLOBAL_SETUP` macro to define the hook function.

This change poisons the whole slot of the object rather than just the flags.
This allows ASAN to find any reads/writes into the slot after it has been
freed.

Newer GCCs have __has_feature and older ones have
__SANITIZE_ADDRESS__[1]. Relevant since ASAN with GCC 11 on the popular
Ubuntu Jammy failed to build previously.

[1]: https://gcc.gnu.org/onlinedocs/gcc-4.8.0/cpp/Common-Predefined-Macros.html

There's no case for when RUBY_MSAN_ENABLED, so the macro ends up doing
nothing when it should instead have __attribute__((__no_sanitize__("memory"))).

```
internal/sanitizers.h:57:26: error: ISO C does not allow extra ‘;’ outside of a function [-Wpedantic]
   57 |     COMPILER_WARNING_PUSH; \
      |                          ^
```

and so many.

Remove semicolons following pragma, and repeat the given declaration
at the end to consume a semicolon following the macro call.  As many
`NO_SANITIZE` calls including bigdecimal that is a gem have a trailing
semicolon, it was not able to move the semicolon inside `NO_SANITIZE`.

Otherwise trying to deref the pointer can cause an ASAN crash, even
though the only reason we're dereferencing it is so that we can assert
on it.