Avoid calling GC in Context::New

TestShellActivity now sets V8 flag --expose_gc, and it should have the same effect to page cycler performance.
diff --git a/V8Binding/v8/src/api.cc b/V8Binding/v8/src/api.cc
index 979ab2e..4222353 100644
--- a/V8Binding/v8/src/api.cc
+++ b/V8Binding/v8/src/api.cc
@@ -2589,8 +2589,13 @@
   i::Handle<i::Context> env;
   {
     ENTER_V8;
+#if defined(ANDROID)
+    // On mobile device, full GC is expensive, leave it to the system to
+    // decide when should make a full GC.
+#else
     // Give the heap a chance to cleanup if we've disposed contexts.
     i::Heap::CollectAllGarbageIfContextDisposed();
+#endif
     v8::Handle<ObjectTemplate> proxy_template = global_template;
     i::Handle<i::FunctionTemplateInfo> proxy_constructor;
     i::Handle<i::FunctionTemplateInfo> global_constructor;