Cleanup the namer, and add a test with fields that used to clash with internal names used by the co…

sdk/lib/_internal/compiler/implementation/ssa/variable_allocator.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 /**
  * The [LiveRange] class covers a range where an instruction is live.
  */
 class LiveRange {
@@ skipping 454 matching lines @@
       String name = names.getName(instruction);
       if (name != null) {
         usedNames.add(name);
         names.addNameUsed(name);
       }
     });
   }
 
   String allocateWithHint(String originalName) {
     int i = 0;
-    String name = JsNames.getValid(originalName);
+    JavaScriptBackend backend = compiler.backend;
+    String name = backend.namer.safeName(originalName);
     while (usedNames.contains(name)) {
-      name = JsNames.getValid('$originalName${i++}');
+      name = backend.namer.safeName('$originalName${i++}');
     }
     return name;
   }
 
   String allocateTemporary() {
     while (!freeTemporaryNames.isEmpty) {
       String name = freeTemporaryNames.removeLast();
       if (!usedNames.contains(name)) return name;
     }
     String name = 't${temporaryIndex++}';
@@ skipping 171 matching lines @@
       if (!needsName(input)) {
         names.addAssignment(predecessor, input, phi);
       } else {
         names.addCopy(predecessor, input, phi);
       }
     }
 
     namer.allocateName(phi);
   }
 }