Add some hostside scripts to make life easier

- Take a heapdump and open it with ahat on the browser:
runhat2 PID_OR_PROCESS_NAME

- Take thread stacktrace dump
stacktrace PID_OR_PROCESS_NAME

TODO: Remove runhat? Is there anyone still using it?

Bug: 110088132
Test: stacktrace system_server
Test: stacktrace $(pid system_server)
Test: stacktrace com.android.systemui
Test: runhat2 system_server
Change-Id: I8ee4b51ac9097d5342d2d4209407a4b8ac4d5945

scripts/stacktrace

@@ -0,0 +1,64 @@
+#!/bin/bash
+
+# Copyright (C) 2018 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -e
+. "${0%/*}"/bash_util.bash
+
+function usage() {
+    cat 1>&2 <<"EOF"
+
+  $script_name: print stacktrace of an android process.
+
+  Usage: $script_name PID_OR_PROCESS_NAME
+
+EOF
+    exit 1
+}
+
+pid="$(resolve_pid "$1" || usage)"
+
+info "Dumping stacktrace from pid $pid ..."
+
+# Send sigquit to initiate stacktrace.
+ts="$(get_last_logcat_timestamp)"
+do_adb shell kill -s sigquit "$pid"
+
+
+# Watch logcat to catch finish, and then obtain the filename.
+
+# First, set up a timer for timeout.
+(
+    sleep 10
+    warn "Timed out waiting for tombstoned. (wrong PID?)"
+    kill -s usr1 $$
+) &
+timer_pid=$!
+
+trap 'exit 0' USR1
+
+# --------- beginning of main
+# 06-14 00:12:57.384  1058   925   925 E /system/bin/tombstoned: Traces for pid 1204 written to: /data/anr/trace_01
+
+info "Waiting for tombstoned to finish writing..."
+
+log="$(do_adb logcat -T "$ts" -e "Traces for pid $pid written to" -m 1 | sed -e 1d)" # Remoe the header
+
+file="${log## }" # Remove everything until the last space.
+
+do_adb shell cat "$file" || true # Somehow this returns 1?
+
+# Success, kill the timer process.
+kill "$timer_pid"