GDScript: Don't warn on unassigned for builtin-typed variables

If the type of a variable is a built-in Variant type, then it will
automatically be assigned a default value based on the type. This means
that the explicit initialization may be unnecessary. Thus this commit
removes the warning in such case.

This also changes the meaning of the unassigned warning to happen when
the variable is used before being assigned, not when it has zero
assignments.

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

@@ -11,6 +11,7 @@ class InnerClass:
 		var e2: InnerClass.MyEnum
 		var e3: EnumTypecheckOuterClass.InnerClass.MyEnum
 
+		@warning_ignore("unassigned_variable")
 		print("Self ", e1, e2, e3)
 		e1 = MyEnum.V1
 		e2 = MyEnum.V1
@@ -48,6 +49,7 @@ func test_outer_from_outer():
 	var e1: MyEnum
 	var e2: EnumTypecheckOuterClass.MyEnum
 
+	@warning_ignore("unassigned_variable")
 	print("Self ", e1, e2)
 	e1 = MyEnum.V1
 	e2 = MyEnum.V1
@@ -66,6 +68,7 @@ func test_inner_from_outer():
 	var e1: InnerClass.MyEnum
 	var e2: EnumTypecheckOuterClass.InnerClass.MyEnum
 
+	@warning_ignore("unassigned_variable")
 	print("Inner ", e1, e2)
 	e1 = InnerClass.MyEnum.V1
 	e2 = InnerClass.MyEnum.V1

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

@@ -0,0 +1,7 @@
+# GH-88117, GH-85796
+
+func test():
+	var array: Array
+	# Should not emit unassigned warning because the Array type has a default value.
+	array.assign([1, 2, 3])
+	print(array)

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

@@ -0,0 +1,2 @@
+GDTEST_OK
+[1, 2, 3]

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

@@ -31,8 +31,8 @@ func int_func() -> int:
 func test_warnings(unused_private_class_variable):
 	var t = 1
 
-	@warning_ignore("unassigned_variable")
 	var unassigned_variable
+	@warning_ignore("unassigned_variable")
 	print(unassigned_variable)
 
 	var _unassigned_variable_op_assign