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/multiline_dictionaries.gd

@@ -0,0 +1,10 @@
+func test():
+	var __ = {
+		"multiline": "dictionary","should": "work",
+		"even with": "a trailing comma",
+	}
+
+	__ = {
+		this_also_applies = "to the",
+		lua_style_syntax = null,	    	foo = null,
+	}