Revert of Swarm tests on Linux release tester. (patchset #2 id:20001 of...

Revert of Swarm tests on Linux release tester. (patchset #2 id:20001 of https://codereview.chromium.org/598053002/)

Reason for revert:
since I disabled the recipe side

Original issue's description:
> Swarm tests on Linux release tester.
>
> BUG=414808
> TBR=maruel@chromium.org
>
> Committed: https://chromium.googlesource.com/chromium/src/+/01b2eb0b5e291faa238d6a21def3e62056bc1fdd

TBR=maruel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=414808

Review URL: https://codereview.chromium.org/602603004

Cr-Commit-Position: refs/heads/master@{#296438}

testing/buildbot/chromium.linux.json

@@ -5,37 +5,16 @@
       "app_list_unittests",
       "app_shell_browsertests",
       "aura_unittests",
-      {
-        "test": "base_unittests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
-      {
-        "test": "browser_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true,
-          "shards": 5
-        }
-      },
+      "base_unittests",
+      "browser_tests",
       "cacheinvalidation_unittests",
       "cast_unittests",
       "cc_unittests",
       "chromedriver_unittests",
       "components_unittests",
       "compositor_unittests",
-      {
-        "test": "content_browsertests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
-      {
-        "test": "content_unittests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
+      "content_browsertests",
+      "content_unittests",
       "crypto_unittests",
       "dbus_unittests",
       "device_unittests",
@@ -46,12 +25,7 @@
       "gfx_unittests",
       "google_apis_unittests",
       "gpu_unittests",
-      {
-        "test": "interactive_ui_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
+      "interactive_ui_tests",
       "ipc_mojo_unittests",
       "ipc_tests",
       "jingle_unittests",
@@ -68,31 +42,16 @@
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "nacl_loader_unittests",
-      {
-        "test": "net_unittests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
+      "net_unittests",
       "ppapi_unittests",
       "printing_unittests",
       "remoting_unittests",
       "sandbox_linux_unittests",
       "sql_unittests",
       "ui_unittests",
-      {
-        "test": "sync_integration_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
+      "sync_integration_tests",
       "sync_unit_tests",
-      {
-        "test": "unit_tests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
+      "unit_tests",
       "url_unittests",
       "views_unittests",
       "wm_unittests"
@@ -234,12 +193,7 @@
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "nacl_loader_unittests",
-      {
-        "test": "net_unittests",
-        "swarming": {
-          "can_use_on_swarming_builders": true
-        }
-      },
+      "net_unittests",
       "ppapi_unittests",
       "printing_unittests",
       "remoting_unittests",