Revert "Add Telemetry to linux-chromiumos bot"

This reverts commit e724b177.

Reason for revert: There have been a series of flakes on the trybots, that were no occurring on the Mojo FYI bots. Removing these tests from the trybots until we can find out why.

Original change's description:
> Add Telemetry to linux-chromiumos bot
> 
> We've been running telemetry_unittests and telemetry_perf_unittests on the Mojo
> FYI bots. They've been cycling green for a week, so we'd like to add them to
> the main linux_chromeos bot.
> 
> TBR=sky@chromium.org
> 
> Bug: 758065
> Change-Id: I6ea2c3f619237124ebba5b691ac08bffb93652a6
> Reviewed-on: https://chromium-review.googlesource.com/657858
> Commit-Queue: Jonathan Ross <jonross@chromium.org>
> Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#503031}

TBR=sadrul@chromium.org,sky@chromium.org,jonross@chromium.org

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

Bug: 758065
Change-Id: I682ef5e4c7ac45384ce4b4c435ab19f23f0b80ec
Reviewed-on: https://chromium-review.googlesource.com/696301Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505877}

testing/buildbot/chromium.chromiumos.json

@@ -493,37 +493,6 @@
         },
         "test": "wm_unittests"
       }
-    ],
-    "isolated_scripts": [
-      {
-        "args": [
-          "--browser=exact",
-          "--browser-executable=./test_chrome",
-          "--xvfb",
-          "--skip=scripts_smoke_unittest.ScriptsSmokeTest.testRunTelemetryBenchmarkAsGoogletest"
-        ],
-        "isolate_name": "telemetry_perf_unittests",
-        "name": "telemetry_perf_unittests",
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "hard_timeout": 960,
-          "shards": 12
-        }
-      },
-      {
-        "args": [
-          "--browser=exact",
-          "--browser-executable=./test_chrome",
-          "--jobs=1",
-          "--skip=telemetry.page.page_run_end_to_end_unittest.ActualPageRunEndToEndTests.testTrafficSettings"
-        ],
-        "isolate_name": "telemetry_unittests",
-        "name": "telemetry_unittests",
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "shards": 4
-        }
-      }
     ]
   },
   "Linux ChromiumOS Tests (dbg)(1)": {