[OpenMP] Remove internal linkage from __kmp_wait template (NFC) (#207983)

__kmp_wait in kmp_dispatch.h is a static function template in a header,
so any TU that includes it without instantiating it trips
-Wunused-template (kmp_runtime.cpp, kmp_affinity.cpp, kmp_global.cpp,
kmp_settings.cpp). It is used by kmp_dispatch.cpp and
kmp_dispatch_hier.h. Drop static, which the comment above it already
suggests.

Part of #202945

GitOrigin-RevId: 29f1a71a8d3f12232ccd53bca2442e35396a11a3