GDScript: Fix type certainty for result of ternary operator

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

@@ -0,0 +1,12 @@
+func test():
+	var left_hard_int := 1
+	var right_hard_int := 2
+	var result_hard_int := left_hard_int if true else right_hard_int
+	assert(result_hard_int == 1)
+
+	var left_hard_variant := 1 as Variant
+	var right_hard_variant := 2.0 as Variant
+	var result_hard_variant := left_hard_variant if true else right_hard_variant
+	assert(result_hard_variant == 1)
+
+	print('ok')

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

@@ -0,0 +1,2 @@
+GDTEST_OK
+ok