Reland of Pass --images '' to nanobench to disable image benchmarking. (patchset #1 id:1 of https://codereview.chromium.org/1400633002/ )

Reason for revert:
Still breaking. e.g.

http://build.chromium.org/p/client.skia/builders/Test-iOS-Clang-iPad4-GPU-SGX554-Arm7-Debug/builds/1466/steps/nanobench/logs/stdio

http://build.chromium.org/p/client.skia.android/builders/Perf-Android-GCC-Nexus7-GPU-Tegra3-Arm7-Release/builds/2280/steps/nanobench/logs/stdio

Original issue's description:
> Revert of Pass --images '' to nanobench to disable image benchmarking. (patchset #1 id:1 of https://codereview.chromium.org/1381703003/ )
>
> Reason for revert:
> I have attempted to fix the problems that caused running nanobench with images to fail, so testing to see if they are in fact fixed.
>
> Original issue's description:
> > Pass --images '' to nanobench to disable image benchmarking.
> >
> > Enabling image benchmarking has caused most nanobench runs to fail,
> > both Debug and Release.
> >
> > BUG=skia:3418
> > NOTREECHECKS=true
> > TBR=scroggo@google.com
> >
> > Committed: https://skia.googlesource.com/skia/+/1f7039c6c5f0f118b629994b0bac255345e5abd6
>
> BUG=skia:3418
>
> Committed: https://skia.googlesource.com/skia/+/c2e59caa0a466040f4b4f08cb5604c86b2615efa

TBR=mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:3418

Review URL: https://codereview.chromium.org/1396843003
diff --git a/tools/nanobench_flags.json b/tools/nanobench_flags.json
index 6084ad1..4f669e1 100644
--- a/tools/nanobench_flags.json
+++ b/tools/nanobench_flags.json
@@ -1,5 +1,6 @@
 {
   "Perf-Android-GCC-NexusPlayer-GPU-PowerVR-x86-Release": [
+    "--images", 
     "--scales", 
     "1.0", 
     "1.1", 
@@ -17,6 +18,7 @@
     "~desk_unicodetable"
   ], 
   "Perf-Android-Nexus7-Tegra3-Arm7-Release": [
+    "--images", 
     "--scales", 
     "1.0", 
     "1.1", 
@@ -35,6 +37,7 @@
     "~desk_carsvg"
   ], 
   "Test-Android-GCC-GalaxyS4-GPU-SGX544-Arm7-Release": [
+    "--images", 
     "--scales", 
     "1.0", 
     "1.1", 
@@ -52,6 +55,7 @@
     "~GLInstancedArraysBench"
   ], 
   "Test-Ubuntu-GCC-ShuttleA-GPU-GTX550Ti-x86_64-Release-Valgrind": [
+    "--images", 
     "--scales", 
     "1.0", 
     "1.1", 
@@ -70,6 +74,7 @@
     "1"
   ], 
   "Test-Win7-MSVC-ShuttleA-GPU-HD2000-x86-Debug-ANGLE": [
+    "--images", 
     "--scales", 
     "1.0", 
     "1.1", 
@@ -91,6 +96,7 @@
     "~etc1bitmap"
   ], 
   "Test-iOS-Clang-iPad4-GPU-SGX554-Arm7-Debug": [
+    "--images", 
     "--scales", 
     "1.0", 
     "1.1", 
diff --git a/tools/nanobench_flags.py b/tools/nanobench_flags.py
index f11ea1f..f590242 100755
--- a/tools/nanobench_flags.py
+++ b/tools/nanobench_flags.py
@@ -29,6 +29,9 @@
 def get_args(bot):
   args = []
 
+  # Temporarily disable image benchmarking.
+  args.append('--images')
+
   if 'Appurify' not in bot:
     args.extend(['--scales', '1.0', '1.1'])