Reland "Switch Win Exp bot to 26.20.100.7870"

This is a reland of e9f81dc4

Failures that caused the revert are semi-expected and only on a
bot marked as experimental.

Original change's description:
> Switch Win Exp bot to 26.20.100.7870
>
> Switches the GPU Win10 Intel experimental bot to trigger tests on
> machins with driver 26.20.100.7870 to test the stability.
>
> TBR=ynovikov@chromium.org
>
> Bug: 1053803
> Change-Id: I3fa8467656312288add0658a3e4b7dfb9c5ac2d8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2111470
> Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
> Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
> Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#751911}

TBR=ynovikov@chromium.org

Bug: 1053803
Change-Id: I9cd2367326cd9314434f0a4f34618e959b605b7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2115777Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752600}

testing/buildbot/mixins.pyl

@@ -678,17 +678,15 @@
       },
     },
   },
-  # TODO(https://crbug.com/1053803): Re-add once the machines are upgraded to
-  # the newer driver version.
-  # 'win10_intel_hd_630_experimental': {
-  #   'swarming': {
-  #     'dimensions': {
-  #       'gpu': '8086:5912-26.20.100.7323',
-  #       'os': 'Windows-10',
-  #       'pool': 'chromium.tests.gpu.template',
-  #     },
-  #   },
-  # },
+  'win10_intel_hd_630_experimental': {
+    'swarming': {
+      'dimensions': {
+        'gpu': '8086:5912-26.20.100.7870',
+        'os': 'Windows-10',
+        'pool': 'chromium.tests.gpu.template',
+      },
+    },
+  },
   'win10_intel_hd_630_stable': {
     'swarming': {
       'dimensions': {

testing/buildbot/waterfalls.pyl

@@ -3462,15 +3462,12 @@
         'browser_config': 'release_x64',
         'mixins': [
           'limited_capacity_bot',
-          'win10_intel_hd_630_stable',
+          'win10_intel_hd_630_experimental',
         ],
         'test_suites': {
-          'gpu_telemetry_tests': 'gpu_noop_sleep_telemetry_test',
-          # TODO(https://crbug.com/1053803): Re-enable tests once the machines
-          # are updated  to the target driver version.
-          # 'gtest_tests': 'gpu_fyi_win_gtests',
-          # 'isolated_scripts': 'gpu_angle_and_desktop_representative_perf_fyi_isolated_scripts',
-          # 'gpu_telemetry_tests': 'gpu_fyi_win_intel_release_telemetry_tests',
+          'gtest_tests': 'gpu_fyi_win_gtests',
+          'isolated_scripts': 'gpu_angle_and_desktop_representative_perf_fyi_isolated_scripts',
+          'gpu_telemetry_tests': 'gpu_fyi_win_intel_release_telemetry_tests',
         },
       },
       'Win10 FYI x64 Exp Release (NVIDIA)': {