[3.13] gh-127065: Make `methodcaller` thread-safe in free threading build (GH-127109) (GH-127150)

The `methodcaller` C vectorcall implementation uses an arguments array
that is shared across calls. The first argument is modified on every
invocation. This isn't thread-safe in the free threading build. I think
it's also not safe in general, but for now just disable it in the free
threading build.
(cherry picked from commit f83ca6962af973fff6a3124f4bd3d45fea4dd5b8)

Co-authored-by: Sam Gross <colesbury@gmail.com>