…free-threading (gh-134686)

Disable immortalization around Py_CompileString*().

The same approach as 332356b that fixed the refleaks in compile() and eval().

E: 09e72cf can pass test_capi, test_sys and test__interpchannels with this patch for me.

…s doc, and add a test to make sure we catch this error in the future. (#134734)

* Add t-string prefixes to _all_string_prefixes, and add a test to make sure we catch this error in the future.

* Update lexical analysis docs for t-string prefixes.

This reverts commit 8a793c4, AKA gh-134599.

This effectively re-applies commit 09e72cf (gh-134511)

…inter in `free threading`. (#134702)

Fix performance regression in calling `ctypes` function pointer in `free threading`.