chore: fixe rest of comments tests.

js/js.translator/testData/js-optimizer/if-reduction/assignment.optimized.js

@@ -1,5 +1,6 @@
 function test(n) {
     var result;
+    /*synthetic*/
     result = n >= 0 ? n : -n;
     return result;
 }

js/js.translator/testData/js-optimizer/if-reduction/returnStatement.optimized.js

@@ -1,4 +1,5 @@
 function test(n) {
+    /*synthetic*/
     return n >= 0 ? n : -n;
 }