LibJS: Reorganize tests into subfolders

Libraries/LibJS/Tests/builtins/Proxy/Proxy.js

@@ -0,0 +1,30 @@
+load("test-common.js");
+
+try {
+    new Proxy({}, {});
+
+    assertThrowsError(() => {
+        new Proxy();
+    }, {
+        error: TypeError,
+        message: "Proxy constructor requires at least two arguments",
+    });
+
+    assertThrowsError(() => {
+        Proxy();
+    }, {
+        error: TypeError,
+        message: "Proxy must be called with the 'new' operator",
+    });
+
+    assertThrowsError(() => {
+        new Proxy(1, {});
+    }, {
+        error: TypeError,
+        message: "Expected target argument of Proxy constructor to be object, got 1",
+    });
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}