Add sanitizer support to Apple platforms

[keith]

This adds support for asan, tsan, and ubsan on Apple platforms.

Fixes #4984 and #6932

[trybka]

Yeah, this is generally fine.

I'd note that we also set the following flags when any of the sanitizers are in use:

                    flags = [
                        "-O1",
                        "-gmlt",
                        # All failed checks are fatal.
                        "-fno-sanitize-recover=all",
                        "-fno-omit-frame-pointer",

[keith]

Would you recommend I add those here? I saw some flags in a previous PR that were similar, but I didn't want to add them w/o knowing if it was something that made sense generally or just for google

[trybka]

I think they're generally useful.

These two are recommended by the Clang ASan Usage docs:

• -O1 is to get reasonable performance, especially if your dbg or fastbuild configs default to -O0.
• -fno-omit-frame-pointer gets better stack traces.

For the other two:

• -fno-sanitize-recover=all is a good default if you want tests and whatnot to fail immediately, this will be workflow dependent. For a heavy CI usage, you often just want to catch the first failure.
• -gmlt is just "line number tables only"

YMMV

[keith]

Fair enough! Added them here

[jin]

@trybka could you approve this PR? I'll import it as well.

[keith]

Thanks!