py/obj.h: Add and use mp_obj_is_bool() helper.

Commit d96cfd13e3 introduced a regression in
testing for bool objects, that such objects were in some cases no longer
recognised and bools, eg when using mp_obj_is_type(o, &mp_type_bool), or
mp_obj_is_integer(o).

This commit fixes that problem by adding mp_obj_is_bool(o).  Builds with
MICROPY_OBJ_IMMEDIATE_OBJS enabled check if the object is any of the const
True or False objects.  Builds without it use the old method of ->type
checking, which compiles to smaller code (compared with the former
mentioned method).

Fixes #5538.

py/obj.h

@@ -665,6 +665,12 @@ extern const struct _mp_obj_exception_t mp_const_GeneratorExit_obj;
 // Note: these are kept as macros because inline functions sometimes use much
 // more code space than the equivalent macros, depending on the compiler.
 #define mp_obj_is_type(o, t) (mp_obj_is_obj(o) && (((mp_obj_base_t*)MP_OBJ_TO_PTR(o))->type == (t))) // this does not work for checking int, str or fun; use below macros for that
+#if MICROPY_OBJ_IMMEDIATE_OBJS
+// bool's are immediates, not real objects, so test for the 2 possible values.
+#define mp_obj_is_bool(o) ((o) == mp_const_false || (o) == mp_const_true)
+#else
+#define mp_obj_is_bool(o) mp_obj_is_type(o, &mp_type_bool)
+#endif
 #define mp_obj_is_int(o) (mp_obj_is_small_int(o) || mp_obj_is_type(o, &mp_type_int))
 #define mp_obj_is_str(o) (mp_obj_is_qstr(o) || mp_obj_is_type(o, &mp_type_str))
 #define mp_obj_is_str_or_bytes(o) (mp_obj_is_qstr(o) || (mp_obj_is_obj(o) && ((mp_obj_base_t*)MP_OBJ_TO_PTR(o))->type->binary_op == mp_obj_str_binary_op))
@@ -721,7 +727,7 @@ bool mp_obj_is_true(mp_obj_t arg);
 bool mp_obj_is_callable(mp_obj_t o_in);
 bool mp_obj_equal(mp_obj_t o1, mp_obj_t o2);
 
-static inline bool mp_obj_is_integer(mp_const_obj_t o) { return mp_obj_is_int(o) || mp_obj_is_type(o, &mp_type_bool); } // returns true if o is bool, small int or long int
+static inline bool mp_obj_is_integer(mp_const_obj_t o) { return mp_obj_is_int(o) || mp_obj_is_bool(o); } // returns true if o is bool, small int or long int
 mp_int_t mp_obj_get_int(mp_const_obj_t arg);
 mp_int_t mp_obj_get_int_truncated(mp_const_obj_t arg);
 bool mp_obj_get_int_maybe(mp_const_obj_t arg, mp_int_t *value);

py/objstr.c

@@ -910,7 +910,7 @@ STATIC bool istype(char ch) {
 }
 
 STATIC bool arg_looks_integer(mp_obj_t arg) {
-    return mp_obj_is_type(arg, &mp_type_bool) || mp_obj_is_int(arg);
+    return mp_obj_is_bool(arg) || mp_obj_is_int(arg);
 }
 
 STATIC bool arg_looks_numeric(mp_obj_t arg) {