Revert "Tidy gAborting."

Creates infinite loop: b/18674776.

This reverts commit 015b137efb434528173779bc3ec8d72494456254.

Change-Id: I67fe310d2e95ee2ec37bec842be06fb1123b6f4e
diff --git a/runtime/runtime.h b/runtime/runtime.h
index e334764..39fd910 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -71,11 +71,6 @@
 class Trace;
 class Transaction;
 
-// 0 if not abort, non-zero if an abort is in progress. Used on fatal exit to prevents recursive
-// aborts. Global declaration allows us to disable some error checking to ensure fatal shutdown
-// makes forward progress.
-extern volatile unsigned int gAborting;
-
 typedef std::vector<std::pair<std::string, const void*>> RuntimeOptions;
 
 // Not all combinations of flags are valid. You may not visit all roots as well as the new roots
@@ -180,9 +175,9 @@
     return instance_;
   }
 
-  // Aborts semi-cleanly. Used in the implementation of LOG(FATAL), which most callers should
-  // prefer. Not [[noreturn]] due to returning early in the case of recursive aborts.
-  static void Abort() LOCKS_EXCLUDED(Locks::abort_lock_);
+  // Aborts semi-cleanly. Used in the implementation of LOG(FATAL), which most
+  // callers should prefer.
+  [[noreturn]] static void Abort() LOCKS_EXCLUDED(Locks::abort_lock_);
 
   // Returns the "main" ThreadGroup, used when attaching user threads.
   jobject GetMainThreadGroup() const;