Pass --undefok to DM and nanobench for more graceful branch failure.

scripts/slave/recipes/skia/skia.expected/failed_get_hashes.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "[DEPOT_TOOLS]/gclient.py",
       "config",
       "--spec",
       "cache_dir = None\nsolutions = [{'deps_file': 'DEPS', 'managed': True, 'name': 'skia', 'url': 'https://skia.googlesource.com/skia.git'}]\ntarget_os = ['android']"
     ],
@@ skipping 562 matching lines @@
   },
   {
     "cmd": [
       "[SLAVE_BUILD]/skia/platform_tools/android/bin/android_run_skia",
       "--logcat",
       "-d",
       "nexus_7",
       "-s",
       "015d210a13480604",
       "dm",
+      "--undefok",
       "--verbose",
       "--resourcePath",
       "/storage/emulated/legacy/skiabot/skia_resources",
       "--skps",
       "/storage/emulated/legacy/skiabot/skia_skp/skps",
       "--images",
       "/storage/emulated/legacy/skiabot/skia_images",
       "--writePath",
       "/storage/emulated/legacy/skiabot/skia_dm",
       "--nameByHash",
@@ skipping 74 matching lines @@
   },
   {
     "cmd": [
       "[SLAVE_BUILD]/skia/platform_tools/android/bin/android_run_skia",
       "--logcat",
       "-d",
       "nexus_7",
       "-s",
       "015d210a13480604",
       "nanobench",
+      "--undefok",
       "-i",
       "/storage/emulated/legacy/skiabot/skia_resources",
       "--skps",
       "/storage/emulated/legacy/skiabot/skia_skp/skps",
       "--nocpu",
       "--dummy-flags"
     ],
     "env": {
       "ANDROID_SDK_ROOT": "/home/chrome-bot/android-sdk-linux",
       "SKIA_ANDROID_VERBOSE_SETUP": "1"
@@ skipping 19 matching lines @@
   {
     "cmd": [
       "/home/chrome-bot/android-sdk-linux/platform-tools/adb",
       "-s",
       "015d210a13480604",
       "wait-for-device"
     ],
     "name": "wait for device (3)"
   }
 ]