Revert "weblayer, skew tests: Add M88 skew tests"

This reverts commit 902c49d1.

Reason for revert: Builders do not allow using a floating references. We need to start pinning tags to chromium/src again in order to run skew tests. The error can be seen here, https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8863706392115604464/+/steps/test_pre_run/0/steps/s__trigger__weblayer_instrumentation_test_versions_apk_M88_Client_Tests/0/stdout?format=raw

Original change's description:
> weblayer, skew tests: Add M88 skew tests
>
> This skew test will updated daily by uploading new CIPD packages
> for each tag created in the M88 branch. The m88 reference will point
> to the most recent package uploaded.
>
> Bug: 1147459, 1147455, 1099017, 1041619
> Change-Id: Ib9ae51d2a7379d478cbab68a334c7d2488bf0e8a
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538152
> Auto-Submit: Rakib Hasan <rmhasan@google.com>
> Commit-Queue: Scott Violet <sky@chromium.org>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#827411}

TBR=sky@chromium.org,rmhasan@google.com

Change-Id: I17d5abc780eeba571c4d92793db46ed88ab61d66
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1147459
Bug: 1147455
Bug: 1099017
Bug: 1041619
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537186Reviewed-by: Rakib Hasan <rmhasan@google.com>
Commit-Queue: Rakib Hasan <rmhasan@google.com>
Cr-Commit-Position: refs/heads/master@{#827479}

testing/buildbot/test_suites.pyl

@@ -5971,11 +5971,9 @@
       },
       'weblayer_instrumentation_version_tests': {
         'variants': [
-          'WEBLAYER_IMPL_SKEW_TESTS_M88_NIGHTLY',
           'WEBLAYER_IMPL_SKEW_TESTS_NTH_MILESTONE',
           'WEBLAYER_IMPL_SKEW_TESTS_NTH_MINUS_ONE_MILESTONE',
           'WEBLAYER_IMPL_SKEW_TESTS_NTH_MINUS_TWO_MILESTONE',
-	  'WEBLAYER_CLIENT_SKEW_TESTS_M88_NIGHTLY',
           'WEBLAYER_CLIENT_SKEW_TESTS_NTH_MILESTONE',
           'WEBLAYER_CLIENT_SKEW_TESTS_NTH_MINUS_ONE_MILESTONE',
           'WEBLAYER_CLIENT_SKEW_TESTS_NTH_MINUS_TWO_MILESTONE',

testing/buildbot/variants.pyl

@@ -307,52 +307,6 @@
     ],
     'identifier': 'iPhone X 14.2'
   },
-  'WEBLAYER_IMPL_SKEW_TESTS_M88_NIGHTLY': {
-    'args': [
-      '--test-runner-outdir',
-      '.',
-      '--client-outdir',
-      '.',
-      '--implementation-outdir',
-      '../../weblayer_instrumentation_test_M88/out/Release',
-      '--test-expectations',
-      '../../weblayer/browser/android/javatests/skew/expectations.txt',
-      '--impl-version=88',
-    ],
-    'identifier': 'M88 Implementation Tests',
-    'swarming': {
-      'cipd_packages': [
-        {
-          'cipd_package': 'chromium/testing/weblayer-x86',
-          'location': 'weblayer_instrumentation_test_M88',
-          'revision': 'm88',
-        }
-      ],
-    },
-  },
-  'WEBLAYER_CLIENT_SKEW_TESTS_M88_NIGHTLY': {
-    'args': [
-      '--test-runner-outdir',
-      '.',
-      '--client-outdir',
-      '../../weblayer_instrumentation_test_M88/out/Release',
-      '--implementation-outdir',
-      '.',
-      '--test-expectations',
-      '../../weblayer/browser/android/javatests/skew/expectations.txt',
-      '--client-version=88',
-    ],
-    'identifier': 'M88 Client Tests',
-    'swarming': {
-      'cipd_packages': [
-        {
-          'cipd_package': 'chromium/testing/weblayer-x86',
-          'location': 'weblayer_instrumentation_test_M88',
-          'revision': 'm88',
-        }
-      ],
-    },
-  },
   'WEBLAYER_IMPL_SKEW_TESTS_NTH_MILESTONE': {
     'args': [
       '--test-runner-outdir',
@@ -491,4 +445,4 @@
       ],
     },
   },
-}
+}
\ No newline at end of file