Add support for tracking jvmti allocations

Adds a jvmti extension for getting the amount of memory allocated and
by jvmtiEnvs and currently live.

Bug: 62065509
Test: ./test.py --host -j40
Change-Id: I5d05b171260d91f9c415f7a5cb40cc01b48d7d07
diff --git a/runtime/openjdkjvmti/ti_allocator.h b/runtime/openjdkjvmti/ti_allocator.h
index 7f1aa6d..aba77ae 100644
--- a/runtime/openjdkjvmti/ti_allocator.h
+++ b/runtime/openjdkjvmti/ti_allocator.h
@@ -35,12 +35,17 @@
 #include "jni.h"
 #include "jvmti.h"
 
+#include <atomic>
+
 namespace openjdkjvmti {
 
 class AllocUtil {
  public:
   static jvmtiError Allocate(jvmtiEnv* env, jlong size, unsigned char** mem_ptr);
   static jvmtiError Deallocate(jvmtiEnv* env, unsigned char* mem);
+  static jvmtiError GetGlobalJvmtiAllocationState(jvmtiEnv* env, jlong* total_allocated);
+ private:
+  static std::atomic<jlong> allocated;
 };
 
 }  // namespace openjdkjvmti