Add an internal flag to the dart2js compiler to enable/diable inlining

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index bf79a1efc38e9aadf92f818c9b8e3981c3e9d666..e87155715d8ce3973deea4953d1e0aabc63394ba 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -1011,6 +1011,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
   bool tryInlineMethod(Element element,
                        Selector selector,
                        Link<Node> arguments) {
+    if (compiler.disableInlining) return false;
     // TODO(floitsch): we should be able to inline inside lazy initializers.
     if (!currentElement.isFunction()) return false;
     // TODO(floitsch): we should be able to inline getters, setters and