Fix GDScript base and outer classes, signals and functions lookup order

- Add outer class lookup test
- Add signal lookup test

Co-authored-by: Dmitrii Maganov <vonagam@gmail.com>

modules/gdscript/tests/scripts/analyzer/features/lookup_class.gd

@@ -0,0 +1,50 @@
+# Inner-outer class lookup
+class A:
+    const Q: = "right one"
+
+class X:
+    const Q: = "wrong one"
+
+class Y extends X:
+    class B extends A:
+        static func check() -> void:
+            print(Q)
+
+# External class lookup
+const External: = preload("lookup_class_external.notest.gd")
+
+class Internal extends External.A:
+    static func check() -> void:
+        print(TARGET)
+
+    class E extends External.E:
+        static func check() -> void:
+            print(TARGET)
+            print(WAITING)
+
+# Variable lookup
+class C:
+    var Q := 'right one'
+
+class D:
+    const Q := 'wrong one'
+
+class E extends D:
+    class F extends C:
+        func check() -> void:
+            print(Q)
+
+# Test
+func test() -> void:
+    # Inner-outer class lookup
+    Y.B.check()
+    print("---")
+
+    # External class lookup
+    Internal.check()
+    Internal.E.check()
+    print("---")
+
+    # Variable lookup
+    var f: = E.F.new()
+    f.check()

modules/gdscript/tests/scripts/analyzer/features/lookup_class.out

@@ -0,0 +1,8 @@
+GDTEST_OK
+right one
+---
+wrong
+right
+godot
+---
+right one

modules/gdscript/tests/scripts/analyzer/features/lookup_class_external.notest.gd

@@ -0,0 +1,15 @@
+class A:
+	const TARGET: = "wrong"
+
+	class B:
+		const TARGET: = "wrong"
+		const WAITING: = "godot"
+
+		class D extends C:
+			pass
+
+class C:
+	const TARGET: = "right"
+
+class E extends A.B.D:
+	pass

modules/gdscript/tests/scripts/analyzer/features/lookup_signal.gd

@@ -0,0 +1,41 @@
+signal hello
+
+func get_signal() -> Signal:
+    return hello
+
+class A:
+    signal hello
+
+    func get_signal() -> Signal:
+        return hello
+
+    class B:
+        signal hello
+
+        func get_signal() -> Signal:
+            return hello
+
+class C extends A.B:
+    func get_signal() -> Signal:
+        return hello
+
+func test():
+    var a: = A.new()
+    var b: = A.B.new()
+    var c: = C.new()
+
+    var hello_a_result: = hello == a.get_signal()
+    var hello_b_result: = hello == b.get_signal()
+    var hello_c_result: = hello == c.get_signal()
+    var a_b_result: = a.get_signal() == b.get_signal()
+    var a_c_result: = a.get_signal() == c.get_signal()
+    var b_c_result: = b.get_signal() == c.get_signal()
+    var c_c_result: = c.get_signal() == c.get_signal()
+
+    print("hello == A.hello? %s" % hello_a_result)
+    print("hello == A.B.hello? %s" % hello_b_result)
+    print("hello == C.hello? %s" % hello_c_result)
+    print("A.hello == A.B.hello? %s" % a_b_result)
+    print("A.hello == C.hello? %s" % a_c_result)
+    print("A.B.hello == C.hello? %s" % b_c_result)
+    print("C.hello == C.hello? %s" % c_c_result)

modules/gdscript/tests/scripts/analyzer/features/lookup_signal.out

@@ -0,0 +1,8 @@
+GDTEST_OK
+hello == A.hello? false
+hello == A.B.hello? false
+hello == C.hello? false
+A.hello == A.B.hello? false
+A.hello == C.hello? false
+A.B.hello == C.hello? false
+C.hello == C.hello? true