[ASan] introduce MONO_NO_SANITIZE_ADDRESS macro and mark sgen pin object scanning function as such
ASan has very few false-positives, quoting the ASan documentation
(https://github.com/google/sanitizers/wiki/AddressSanitizer#turning-off-instrumentation):
> In some cases a particular function should be ignored (not instrumented)
> by AddressSanitizer:
>
> [...]
>
> * Ignore a function that does some low-level magic (e.g. walking through
> the thread's stack bypassing the frame boundaries).
>
> [...]