LibJS: Handle return value in switch statement unwinding

Fixes #3790.

Libraries/LibJS/Tests/switch-basic.js

@@ -36,4 +36,17 @@ describe("basic switch tests", () => {
 
         expect().fail();
     });
+
+    test("return from switch statement", () => {
+        function foo(value) {
+            switch (value) {
+                case 42:
+                    return "return from 'case 42'";
+                default:
+                    return "return from 'default'";
+            }
+        }
+        expect(foo(42)).toBe("return from 'case 42'");
+        expect(foo(43)).toBe("return from 'default'");
+    });
 });