LibJS: Correct behaviour of direct vs. indirect eval

eval only has direct access to the local scope when accessed through
the name eval. This includes locals named eval, because of course it
does.

Userland/Libraries/LibJS/Tests/eval-aliasing.js

@@ -0,0 +1,15 @@
+test("variable named 'eval' pointing to another function calls that function", function () {
+    var testValue = "inner";
+    // This breaks prettier as it considers this to be a parse error
+    // before even trying to do any linting
+    var eval = () => {
+        return "wat";
+    };
+    expect(eval("testValue")).toEqual("wat");
+});
+
+test("variable named 'eval' pointing to real eval works as a direct eval", function () {
+    var testValue = "inner";
+    var eval = globalThis.eval;
+    expect(eval("testValue")).toEqual("inner");
+});