py/obj: Optimise mp_obj_get_type for immediate objs with repr A and C.

This function is called often and with immediate objects enabled it has
more cases, so optimise it for speed.  With this optimisation the runtime
is now slightly faster with immediate objects enabled than with them
disabled.

py/obj.c

@@ -38,11 +38,47 @@
 #include "py/stream.h" // for mp_obj_print
 
 const mp_obj_type_t *mp_obj_get_type(mp_const_obj_t o_in) {
+    #if MICROPY_OBJ_IMMEDIATE_OBJS && MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A
+
+    if (mp_obj_is_obj(o_in)) {
+        const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
+        return o->type;
+    } else {
+        static const mp_obj_type_t *const types[] = {
+            NULL, &mp_type_int, &mp_type_str, &mp_type_int,
+            NULL, &mp_type_int, &mp_type_NoneType, &mp_type_int,
+            NULL, &mp_type_int, &mp_type_str, &mp_type_int,
+            NULL, &mp_type_int, &mp_type_bool, &mp_type_int,
+        };
+        return types[(uintptr_t)o_in & 0xf];
+    }
+
+    #elif MICROPY_OBJ_IMMEDIATE_OBJS && MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C
+
+    if (mp_obj_is_small_int(o_in)) {
+        return &mp_type_int;
+    } else if (mp_obj_is_obj(o_in)) {
+        const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
+        return o->type;
+    #if MICROPY_PY_BUILTINS_FLOAT
+    } else if ((((mp_uint_t)(o_in)) & 0xff800007) != 0x00000006) {
+        return &mp_type_float;
+    #endif
+    } else {
+        static const mp_obj_type_t *const types[] = {
+            &mp_type_str, &mp_type_NoneType, &mp_type_str, &mp_type_bool,
+        };
+        return types[((uintptr_t)o_in >> 3) & 3];
+    }
+
+    #else
+
     if (mp_obj_is_small_int(o_in)) {
         return &mp_type_int;
     } else if (mp_obj_is_qstr(o_in)) {
         return &mp_type_str;
-    #if MICROPY_PY_BUILTINS_FLOAT
+    #if MICROPY_PY_BUILTINS_FLOAT && ( \
+        MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D)
     } else if (mp_obj_is_float(o_in)) {
         return &mp_type_float;
     #endif
@@ -55,6 +91,8 @@ const mp_obj_type_t *mp_obj_get_type(mp_const_obj_t o_in) {
         const mp_obj_base_t *o = MP_OBJ_TO_PTR(o_in);
         return o->type;
     }
+
+    #endif
 }
 
 const char *mp_obj_get_type_str(mp_const_obj_t o_in) {