[JS IR] Drop TemporaryAssignmentElimination optimization

Enable TemporaryAssignment tests

js/js.translator/testData/js-optimizer/temporary-assignment/transitiveChain.optimized.js

@@ -3,22 +3,19 @@ function f(x) {
 }
 
 function testRegular() {
-    var result;
-    result = f("testRegular");
+    var result = f("testRegular");
     return result;
 }
 
 function testIrregular() {
-    var result;
-    result = f("testIrregular");
+    var result = f("testIrregular");
     return result;
 }
 
 function testDoubleUse1() {
-    var result;
     var $b;
     $b = f("testDoubleUse1");
-    result = $b;
+    var result = $b;
     f($b);
     return result;
 }
@@ -32,10 +29,9 @@ function testDoubleUse2() {
 }
 
 function testDoubleUse3() {
-    var result;
     var $a;
     $a = f("testDoubleUse3");
-    result = $a;
+    var result = $a;
     f($a);
     return result;
 }
@@ -68,4 +64,4 @@ function box() {
     if (result != "testCircular") return "failCircular: " + result;
 
     return "OK"
-}
+}