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/runtime_options.def b/runtime/runtime_options.def
index 097bccb..838d1a9 100644
--- a/runtime/runtime_options.def
+++ b/runtime/runtime_options.def
@@ -67,6 +67,7 @@
 RUNTIME_OPTIONS_KEY (bool,                UseTLAB,                        (kUseTlab || kUseReadBarrier))
 RUNTIME_OPTIONS_KEY (bool,                EnableHSpaceCompactForOOM,      true)
 RUNTIME_OPTIONS_KEY (bool,                UseJIT,                         false)
+RUNTIME_OPTIONS_KEY (bool,                DumpNativeStackOnSigQuit,       true)
 RUNTIME_OPTIONS_KEY (unsigned int,        JITCompileThreshold,            jit::Jit::kDefaultCompileThreshold)
 RUNTIME_OPTIONS_KEY (unsigned int,        JITWarmupThreshold,             jit::Jit::kDefaultWarmupThreshold)
 RUNTIME_OPTIONS_KEY (MemoryKiB,           JITCodeCacheInitialCapacity,    jit::JitCodeCache::kInitialCapacity)