[compiler-rt] Remove maximum OSX version for sanitizers (PR #77543)

[Julian Lettner via llvm-commits]

yln wrote:

> > For building, if we want to intercept a newly-introduced API we usually "forward declare" the API (copy the minimal set of declarations necessary from the headers) in compiler-rt itself. This enables us to add interceptors for APIs without requiring all builders of compiler-rt to use the new SDK that declares this API.
> 
> @yln could you point me to an example of this? I'm trying to find one for `os_unfair_lock_lock` but can't seem to find the forward declaration in the llvm-project source tree.

The libdispatch APIs here (added in e0e02444bc17f83d995a26d9cc47ba3166cfcea4):
https://github.com/llvm/llvm-project/blob/8246b2e156568c31e71e16cbaf4c14d316e7c06e/compiler-rt/lib/tsan/rtl/tsan_dispatch_defs.h#L17

Albeit the reason wasn't to intercept a new API, but to reduce our dependencies on the SDK.

> > On a different note: I am open to bumping the minimal deployment target (even if not strictly necessary) if it eases the maintenance burden.
> 
> Let me know if you'd like to see this in this review, or a future one, and what version to move it to. As mentioned in the wall of text there are some deprecation warnings in newer versions while building, but no build errors.

In a separate PR please and with some justification "What does it buy us?".  This will require extensive qualification on our side.  I am deferring to @thetruestblue who already did some investigation on this.

https://github.com/llvm/llvm-project/pull/77543