ART: Factor out native stack dumping

Move DumpNativeStack and DumpKernelStack into a new file to keep
concerns separated. Clean up the file.

In preparation for modifications to how we use addr2line.

Bug: 30351473
Test: m test-art-host
Test: manual host testing with a test that times out
Change-Id: I02d5645952fe94fd8e73bcf0522721547f6cef66
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 9f0ef7c..50bea65 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -115,6 +115,7 @@
 #include "native/org_apache_harmony_dalvik_ddmc_DdmVmInternal.h"
 #include "native/sun_misc_Unsafe.h"
 #include "native_bridge_art_interface.h"
+#include "native_stack_dump.h"
 #include "oat_file.h"
 #include "oat_file_manager.h"
 #include "os.h"