py/runtime: Reorder mp_handle_pending_behaviour_t enum.

This is functionally a no-op, although will change compiled code due to the
numerical values of the enums changing.

This is needed for a follow-up commit, to remove the static-inline
`mp_handle_pending(bool)` helper function.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

py/runtime.h

@@ -52,10 +52,11 @@ typedef enum {
     MP_ARG_KW_ONLY   = 0x200,
 } mp_arg_flag_t;
 
+// These first two enum values match the original signature of `mp_handle_pending(bool)`.
 typedef enum {
+    MP_HANDLE_PENDING_CALLBACKS_AND_CLEAR_EXCEPTIONS = false,
+    MP_HANDLE_PENDING_CALLBACKS_AND_EXCEPTIONS = true,
     MP_HANDLE_PENDING_CALLBACKS_ONLY,
-    MP_HANDLE_PENDING_CALLBACKS_AND_EXCEPTIONS,
-    MP_HANDLE_PENDING_CALLBACKS_AND_CLEAR_EXCEPTIONS,
 } mp_handle_pending_behaviour_t;
 
 typedef union _mp_arg_val_t {