pybricks/tools/pb_type_awaitable: Share blocking assert.

We want to call this from most class inits.

pybricks/tools.h

@@ -14,6 +14,8 @@ void pb_module_tools_init(void);
 
 bool pb_module_tools_run_loop_is_active(void);
 
+void pb_module_tools_assert_blocking(void);
+
 extern const mp_obj_type_t pb_type_StopWatch;
 
 extern const mp_obj_type_t pb_type_Task;

pybricks/tools/pb_module_tools.c

@@ -31,6 +31,12 @@ bool pb_module_tools_run_loop_is_active() {
     return run_loop_is_active;
 }
 
+void pb_module_tools_assert_blocking(void) {
+    if (run_loop_is_active) {
+        mp_raise_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("This can only be called before multitasking starts."));
+    }
+}
+
 // The awaitables for the wait() function have no object associated with
 // it (unlike e.g. a motor), so we make a starting point here. These never
 // have to cancel each other so shouldn't need to be in a list, but this lets

pybricks/tools/pb_type_awaitable.c

@@ -195,7 +195,7 @@ mp_obj_t pb_type_awaitable_await_or_wait(
 
         // Some operations are not allowed in async mode.
         if (options & PB_TYPE_AWAITABLE_OPT_FORCE_BLOCK) {
-            mp_raise_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("This can only be called before multitasking starts."));
+            pb_module_tools_assert_blocking();
         }
 
         // First cancel linked awaitables if requested.