Fix invalid syntax for JS setters in tests

LayoutTests/fast/js/script-tests/implicit-call-with-global-reentry.js

 description(
 "This test checks that implicit reentry to global code through a getter does not clobber the calling register file."
 );
 
 var testVar = "FAIL";
 function testGlobalCode(test) {
     document.write("<script>"+test+"<"+"/script>");
 }
 var testObject = {
     get getterTest(){ testGlobalCode("var a, b, c, d; testVar = 'PASS';"); },
-    set setterTest(){ testGlobalCode("var e, f, g, h; testVar = 'PASS';"); },
+    set setterTest(_){ testGlobalCode("var e, f, g, h; testVar = 'PASS';"); },
     toString: function() { testGlobalCode("var i, j, k, l; testVar = 'PASS';"); return ''; },
     valueOf: function() { testGlobalCode("var m, n, o, p; testVar = 'PASS';"); return 0; },
     toStringTest: function() { "" + this; },
     valueOfTest: function() { 0 * this; }
 };
 
 shouldBe("testObject.getterTest; testVar;", '"PASS"');
 var testVar = "FAIL";
 shouldBe("testObject.setterTest = 1; testVar;", '"PASS"');
 var testVar = "FAIL";
 shouldBe("testObject.toStringTest(); testVar;", '"PASS"');
 var testVar = "FAIL";
 shouldBe("testObject.valueOfTest(); testVar;", '"PASS"');