LibJS/Tests: Use canParseSource() for toEval()

We can now enable the "new.target is syntax error outside of function"
test :^)

Libraries/LibJS/Tests/automatic-semicolon-insertion.js

@@ -1,18 +1,18 @@
 test("Issue #1829, if-else without braces or semicolons", () => {
     const source = `if (1)
-    return 1;
+    foo;
 else
-    return 0;
+    bar;
 
 if (1)
-    return 1
+    foo
 else
-    return 0
+    bar
 
 if (1)
-    return 1
+    foo
 else
-    return 0;`;
+    bar;`;
 
     expect(source).toEval();
 });

Libraries/LibJS/Tests/functions/function-new-target.js

@@ -20,7 +20,6 @@ test("basic functionality", () => {
     expect(new baz().newTarget).toEqual(baz);
 });
 
-// FIXME: This does not work as expected as toEval() places the code inside a function :|
-test.skip("syntax error outside of function", () => {
+test("syntax error outside of function", () => {
     expect("new.target").not.toEval();
 });

Libraries/LibJS/Tests/test-common-tests.js

@@ -326,13 +326,11 @@ test("toThrowWithMessage", () => {
     expect(thrower).not.toThrowWithMessage(TypeError, "foo baz");
 });
 
-// FIXME: Will have to change when this matcher changes to use the
-// "eval" function
 test("toEval", () => {
     expect("let a = 1").toEval();
     expect("a < 1").toEval();
     expect("&&*^%#%@").not.toEval();
-    expect("function foo() { return 1; }; return foo();").toEval();
+    expect("function foo() { return 1; }; foo();").toEval();
 });
 
 // FIXME: Will have to change when this matcher changes to use the

Libraries/LibJS/Tests/test-common.js

@@ -302,14 +302,8 @@ class ExpectationError extends Error {
         // Test for syntax errors; target must be a string
         toEval() {
             this.__expect(typeof this.target === "string");
-
-            let threw = false;
-            try {
-                new Function(this.target);
-            } catch (e) {
-                threw = true;
-            }
-            this.__expect(this.inverted ? threw : !threw);
+            const success = canParseSource(this.target)
+            this.__expect(this.inverted ? !success : success);
         }
 
         // Must compile regardless of inverted-ness