Fix runners to do their best to gracefully stop on pod eviction (#1759)

Ref #1535
Ref #1581

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

runner/wait.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+function wait_for_process () {
+    local max_time_wait=30
+    local process_name="$1"
+    local waited_sec=0
+    while ! pgrep "$process_name" >/dev/null && ((waited_sec < max_time_wait)); do
+        log.debug "Process $process_name is not running yet. Retrying in 1 seconds"
+        log.debug "Waited $waited_sec seconds of $max_time_wait seconds"
+        sleep 1
+        ((waited_sec=waited_sec+1))
+        if ((waited_sec >= max_time_wait)); then
+            return 1
+        fi
+    done
+    return 0
+}