Use "not" instead of the exclamation mark in GDScript files

Also add String casts

2d/physics_tests/tests/functional/test_collision_pairs.gd

@@ -92,7 +92,7 @@ func _initialize_collision_shapes():
 	for node in $Shapes.get_children():
 		var body = node as PhysicsBody2D
 		var shape = body.shape_owner_get_shape(0, 0)
-		shape.resource_name = node.name.substr("RigidBody".length())
+		shape.resource_name = String(node.name).substr("RigidBody".length())
 
 		_collision_shapes.push_back(shape)
 

2d/physics_tests/tests/functional/test_raycasting.gd

@@ -25,7 +25,7 @@ func _physics_process(_delta):
 	for node in $Shapes.get_children():
 		var body = node as PhysicsBody2D
 		var space_state = body.get_world_2d().direct_space_state
-		var body_name = body.name.substr("RigidBody".length())
+		var body_name = String(body.name).substr("RigidBody".length())
 
 		Log.print_log("* Testing: %s" % body_name)
 
@@ -45,7 +45,7 @@ func _physics_process(_delta):
 		res = _add_raycast(space_state, center, center + Vector2(0, 40))
 		Log.print_log("Raycast inside: %s" % ("HIT" if res else "NO HIT"))
 
-		if body.name.ends_with("ConcavePolygon"):
+		if String(body.name).ends_with("ConcavePolygon"):
 			# Raycast inside an internal face.
 			center.x += 20
 			res = _add_raycast(space_state, center, center + Vector2(0, 40))

2d/physics_tests/tests/performance/test_perf_contacts.gd

@@ -91,7 +91,7 @@ func _on_option_selected(option):
 func _find_type_index(type_name):
 	for type_index in range(_object_templates.size()):
 		var type_node = _object_templates[type_index]
-		if type_node.name.find(type_name) > -1:
+		if String(type_node.name).find(type_name) > -1:
 			return type_index
 
 	Log.print_error("Invalid shape type: " + type_name)