Revert "Switch Win Exp bot to 26.20.100.7870"

This reverts commit e9f81dc4.

Reason for revert: https://bugs.chromium.org/p/chromium/issues/detail?id=1063845

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,bsheedy@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1053803,1063845
Change-Id: I1550fb41247be307defaa184c5bdd4be80a75ab6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2115458
Commit-Queue: Peng Huang <penghuang@chromium.org>
Reviewed-by: Peng Huang <penghuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752471}

testing/buildbot/mixins.pyl

@@ -670,15 +670,17 @@
       },
     },
   },
-  'win10_intel_hd_630_experimental': {
-    'swarming': {
-      'dimensions': {
-        'gpu': '8086:5912-26.20.100.7870',
-        'os': 'Windows-10',
-        'pool': 'chromium.tests.gpu.template',
-      },
-    },
-  },
+  # 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_stable': {
     'swarming': {
       'dimensions': {

testing/buildbot/waterfalls.pyl

@@ -3449,12 +3449,15 @@
         'browser_config': 'release_x64',
         'mixins': [
           'limited_capacity_bot',
-          'win10_intel_hd_630_experimental',
+          'win10_intel_hd_630_stable',
         ],
         'test_suites': {
-          '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',
+          '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',
         },
       },
       'Win10 FYI x64 Exp Release (NVIDIA)': {