Revert r-25106, js semantics for numbers pop up again.

sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart

Index: sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart	(revision 25109)
+++ sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart	(working copy)
@@ -384,13 +384,6 @@
 
   TypeMask visitOperatorSend(Send node) {
     Operator op = node.selector;
-    if (node.isPrefix) {
-      // Cheap check for -literal.
-      if (node.receiver.asLiteralInt() != null
-          || node.receiver.asLiteralDouble() != null) {
-        return visit(node.receiver);
-      }
-    }
     if (const SourceString("[]") == op.source) {
       return visitDynamicSend(node);
     } else if (const SourceString("&&") == op.source) {