init: dump stack when aborting

Dump init stacks when aborting either due to LOG(FATAL) or in
userdebug/eng builds due to signals, including signals from
sanitizers.

Doesn't work for static first stage init yet, b/133450393 tracks
that.

Also, ensure that LOG(FATAL) in child processes calls abort() in all
stages of init, not just 2nd stage init.

Bug: 131747478
Test: abort init in various ways and see stacks
Test: hang or crash in backtrace handler and see child reboot
Change-Id: Ib53b5d3e7e814244203f875de016ada9900dfce8
diff --git a/init/util.h b/init/util.h
index 2232a0f..767620b 100644
--- a/init/util.h
+++ b/init/util.h
@@ -63,7 +63,8 @@
 
 bool IsLegalPropertyName(const std::string& name);
 
-void InitKernelLogging(char** argv, std::function<void(const char*)> abort_function);
+void SetStdioToDevNull(char** argv);
+void InitKernelLogging(char** argv);
 bool IsRecoveryMode();
 }  // namespace init
 }  // namespace android