Now we have a proper C++ library, use std::unique_ptr.

Also remove the Android.libcxx.mk and other bits of stlport compatibility
mechanics.

Change-Id: Icdf7188ba3c79cdf5617672c1cfd0a68ae596a61
diff --git a/runtime/jdwp/jdwp_main.cc b/runtime/jdwp/jdwp_main.cc
index 2419ca6..64e9f37 100644
--- a/runtime/jdwp/jdwp_main.cc
+++ b/runtime/jdwp/jdwp_main.cc
@@ -235,7 +235,7 @@
 JdwpState* JdwpState::Create(const JdwpOptions* options) {
   Thread* self = Thread::Current();
   Locks::mutator_lock_->AssertNotHeld(self);
-  UniquePtr<JdwpState> state(new JdwpState(options));
+  std::unique_ptr<JdwpState> state(new JdwpState(options));
   switch (options->transport) {
     case kJdwpTransportSocket:
       InitSocketTransport(state.get(), options);