gh-116818: Make sys.settrace, sys.setprofile, and monitoring thread-safe (#116775)

Makes sys.settrace, sys.setprofile, and monitoring generally thread-safe.

Mostly uses a stop-the-world approach and synchronization around the code object's _co_instrumentation_version.  There may be a little bit of extra synchronization around the monitoring data that's required to be TSAN clean.

Python/ceval.c

@@ -20,6 +20,7 @@
 #include "pycore_opcode_metadata.h" // EXTRA_CASES
 #include "pycore_optimizer.h"     // _PyUOpExecutor_Type
 #include "pycore_opcode_utils.h"  // MAKE_FUNCTION_*
+#include "pycore_pyatomic_ft_wrappers.h" // FT_ATOMIC_LOAD_PTR_ACQUIRE
 #include "pycore_pyerrors.h"      // _PyErr_GetRaisedException()
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_range.h"         // _PyRangeIterObject