Add an option to disable native stack dumping on SIGQUIT.

Some of our (stress) run-tests do ANR dumping, which end up
stressing libunwind, that has known problems. To avoid getting
flakes due to libunwind, disable native stack dumping on SIGQUIT
for our run-tests.

bug:27185632
bug:24664297
Change-Id: I69085e48db903d6240448d71666ae2dcd091922e
diff --git a/runtime/thread.h b/runtime/thread.h
index 3a5d72e..2726e91 100644
--- a/runtime/thread.h
+++ b/runtime/thread.h
@@ -187,7 +187,9 @@
   void ShortDump(std::ostream& os) const;
 
   // Dumps the detailed thread state and the thread stack (used for SIGQUIT).
-  void Dump(std::ostream& os, BacktraceMap* backtrace_map = nullptr) const
+  void Dump(std::ostream& os,
+            bool dump_native_stack = true,
+            BacktraceMap* backtrace_map = nullptr) const
       REQUIRES(!Locks::thread_suspend_count_lock_)
       SHARED_REQUIRES(Locks::mutator_lock_);
 
@@ -1111,7 +1113,9 @@
   void VerifyStackImpl() SHARED_REQUIRES(Locks::mutator_lock_);
 
   void DumpState(std::ostream& os) const SHARED_REQUIRES(Locks::mutator_lock_);
-  void DumpStack(std::ostream& os, BacktraceMap* backtrace_map = nullptr) const
+  void DumpStack(std::ostream& os,
+                 bool dump_native_stack = true,
+                 BacktraceMap* backtrace_map = nullptr) const
       REQUIRES(!Locks::thread_suspend_count_lock_)
       SHARED_REQUIRES(Locks::mutator_lock_);