Revert of Default SK_ANGLE to true on Windows, run angle whenever possible on bots. (patchset #3 id:40001 of https://codereview.chromium.org/946933006/)

Reason for revert:
Needs bot upgrades.

Original issue's description:
> Default SK_ANGLE to true on Windows, run angle whenever possible on bots.
>
> nanobench doesn't need an update.  It uses the default for --config,
> which includes angle.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/88ec329b580a081d9d56cbcaad0ee46cb941c849

TBR=bsalomon@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/954243002
diff --git a/tools/dm_flags.py b/tools/dm_flags.py
index c41a003..985a62a 100755
--- a/tools/dm_flags.py
+++ b/tools/dm_flags.py
@@ -22,13 +22,15 @@
 def get_args(bot):
   args = []
 
-  configs = ['565', '8888', 'gpu', 'nvprmsaa4', 'angle']
+  configs = ['565', '8888', 'gpu', 'nvprmsaa4']
   # Xoom and NP are running out of RAM when we run all these modes.  skia:3255
   if ('Xoom'        not in bot and
       'NexusPlayer' not in bot):
     configs.extend(mode + '-8888' for mode in
                    ['serialize', 'tiles_rt', 'pipe'])
     configs.append('tiles_rt-gpu')
+  if 'ANGLE' in bot:
+    configs.append('angle')
   args.append('--config')
   args.extend(configs)
 
@@ -86,6 +88,7 @@
     'Test-Android-Xoom-Tegra2-Arm7-Release',
     'Test-ChromeOS-Alex-GMA3150-x86-Debug',
     'Test-Ubuntu12-ShuttleA-GTX550Ti-x86_64-Release-Valgrind',
+    'Test-Win7-ShuttleA-HD2000-x86-Debug-ANGLE',
   ]
 
   cov = coverage.coverage()