py/scope: Use lookup-table to determine a scope's simple name.

Generates slightly smaller and more efficient code.
diff --git a/py/emitcommon.c b/py/emitcommon.c
index 435188f..2925f4c 100644
--- a/py/emitcommon.c
+++ b/py/emitcommon.c
@@ -50,12 +50,12 @@
     bool added;
     id_info_t *id = scope_find_or_add_id(scope, qst, &added);
     if (added) {
-        if (scope->kind == SCOPE_MODULE || scope->kind == SCOPE_CLASS) {
-            id->kind = ID_INFO_KIND_GLOBAL_IMPLICIT;
-        } else {
+        if (SCOPE_IS_FUNC_LIKE(scope->kind)) {
             id->kind = ID_INFO_KIND_LOCAL;
+        } else {
+            id->kind = ID_INFO_KIND_GLOBAL_IMPLICIT;
         }
-    } else if (scope->kind >= SCOPE_FUNCTION && scope->kind <= SCOPE_GEN_EXPR && id->kind == ID_INFO_KIND_GLOBAL_IMPLICIT) {
+    } else if (SCOPE_IS_FUNC_LIKE(scope->kind) && id->kind == ID_INFO_KIND_GLOBAL_IMPLICIT) {
         // rebind as a local variable
         id->kind = ID_INFO_KIND_LOCAL;
     }