Add dozens of new integration tests to the GDScript test suite

This also ignores `.out` files in the file format static checks.

modules/gdscript/tests/scripts/parser/features/dictionary.out

@@ -0,0 +1,14 @@
+GDTEST_OK
+world
+zero point zero
+zero
+zero point zero
+null
+false
+empty array
+zero Vector2i
+{22:{4:[nesting, arrays]}}
+{4:[nesting, arrays]}
+[nesting, arrays]
+nesting
+arrays