Revert^5 "Rewrite JVMTI method tracing to use trampolines"

This reverts commit d7da3147fea647ade418337aed6a8f9402412611.

Reason for revert: Tests are still failing on the buildbot.

Change-Id: Iaaac38137b1c4bed8e3a15b0c0c14730654025f6
diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index 86f0606..ed449b5 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -768,20 +768,13 @@
 void Jit::Stop() {
   Thread* self = Thread::Current();
   // TODO(ngeoffray): change API to not require calling WaitForCompilationToFinish twice.
-  // During shutdown and startup the thread-pool can be null.
-  if (GetThreadPool() == nullptr) {
-    return;
-  }
   WaitForCompilationToFinish(self);
   GetThreadPool()->StopWorkers(self);
   WaitForCompilationToFinish(self);
 }
 
 void Jit::Start() {
-  // During shutdown and startup the thread-pool can be null.
-  if (GetThreadPool() != nullptr) {
-    GetThreadPool()->StartWorkers(Thread::Current());
-  }
+  GetThreadPool()->StartWorkers(Thread::Current());
 }
 
 ScopedJitSuspend::ScopedJitSuspend() {
diff --git a/runtime/jit/jit_code_cache.cc b/runtime/jit/jit_code_cache.cc
index 70a7171..eeb3515 100644
--- a/runtime/jit/jit_code_cache.cc
+++ b/runtime/jit/jit_code_cache.cc
@@ -362,21 +362,6 @@
   return nullptr;
 }
 
-void JitCodeCache::ClearAllCompiledDexCode() {
-  MutexLock mu(Thread::Current(), lock_);
-  // Get rid of OSR code waiting to be put on a thread.
-  osr_code_map_.clear();
-
-  // We don't clear out or even touch method_code_map_ since that is what we use to go the other
-  // way, move from code currently-running to the method it's from. Getting rid of it would break
-  // the jit-gc, stack-walking and signal handling. Since we never look through it to go the other
-  // way (from method -> code) everything is fine.
-
-  for (ProfilingInfo* p : profiling_infos_) {
-    p->SetSavedEntryPoint(nullptr);
-  }
-}
-
 const void* JitCodeCache::FindCompiledCodeForInstrumentation(ArtMethod* method) {
   // If jit-gc is still on we use the SavedEntryPoint field for doing that and so cannot use it to
   // find the instrumentation entrypoint.
diff --git a/runtime/jit/jit_code_cache.h b/runtime/jit/jit_code_cache.h
index ee6111a..49a19a1 100644
--- a/runtime/jit/jit_code_cache.h
+++ b/runtime/jit/jit_code_cache.h
@@ -215,8 +215,6 @@
       REQUIRES(!lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  void ClearAllCompiledDexCode() REQUIRES(!lock_, Locks::mutator_lock_);
-
   void CopyInlineCacheInto(const InlineCache& ic, Handle<mirror::ObjectArray<mirror::Class>> array)
       REQUIRES(!lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);