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/dollar_node_paths.gd

@@ -0,0 +1,20 @@
+extends Node
+
+
+func test():
+	# Create the required node structure.
+	var hello = Node.new()
+	hello.name = "Hello"
+	add_child(hello)
+	var world = Node.new()
+	world.name = "World"
+	hello.add_child(world)
+
+	# All the ways of writing node paths below with the `$` operator are valid.
+	# Results are assigned to variables to avoid warnings.
+	var __ = $Hello
+	__ = $"Hello"
+	__ = $Hello/World
+	__ = $"Hello/World"
+	__ = $"Hello/.."
+	__ = $"Hello/../Hello/World"