Inline TLS access. (mono/mono#16882)

Inline TLS access. (mono/mono#16882)

The same functions are referenced by JIT and runtime.
The JIT uses cannot be inlined. The runtime can.
Since I could not get anything else to build and the change is simple and mechanical, now two sets of functions are provided, inline and extern. Extern just calls inline.
This PR appears to change all the uses, but it is only the JIT uses. The runtime ones just work and keep the old names.

We should also consider building desktop with LTO/LTCG, which would do all this automatically, smarter, more generally. A quick experiment shows it grows the runtime size, which is why I say desktop.

Commit migrated from https://github.com/mono/mono/commit/aca55a42aa5117f4406b68b1ac217063cc7ab3ec