Stop passing --test-launcher-print-test-stdio=always to sandbox_linux_unittests on 4 bots.

If we always want the output, we should add the flag in testing/buildbot/gn_isolate_map.pyl
or waterfalls.pyl for all bots, and not set this for a small arbitrary subset.

Bug: 843511
Change-Id: I8a1e1f32ec22da2b02bc05ac56ecee659b4448ee
Reviewed-on: https://chromium-review.googlesource.com/1136517Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575012}

testing/buildbot/chromium.chromiumos.json

@@ -726,9 +726,6 @@
         "test": "remoting_unittests"
       },
       {
-        "args": [
-          "--test-launcher-print-test-stdio=always"
-        ],
         "swarming": {
           "can_use_on_swarming_builders": true
         },
@@ -1343,9 +1340,6 @@
         "test": "remoting_unittests"
       },
       {
-        "args": [
-          "--test-launcher-print-test-stdio=always"
-        ],
         "swarming": {
           "can_use_on_swarming_builders": true
         },

testing/buildbot/chromium.linux.json

@@ -2221,9 +2221,6 @@
         "test": "remoting_unittests"
       },
       {
-        "args": [
-          "--test-launcher-print-test-stdio=always"
-        ],
         "swarming": {
           "can_use_on_swarming_builders": true
         },
@@ -2920,9 +2917,6 @@
         "test": "printing_unittests"
       },
       {
-        "args": [
-          "--test-launcher-print-test-stdio=always"
-        ],
         "swarming": {
           "can_use_on_swarming_builders": true
         },

testing/buildbot/test_suite_exceptions.pyl

@@ -892,30 +892,6 @@
       'Linux Tests (dbg)(1)(32)',  # https://crbug.com/852895
     ],
   },
-  'sandbox_linux_unittests': {
-    'modifications': {
-      'linux-chromeos-dbg': {
-        'args': [
-          '--test-launcher-print-test-stdio=always',
-        ],
-      },
-      'linux-chromeos-rel': {
-        'args': [
-          '--test-launcher-print-test-stdio=always',
-        ],
-      },
-      'Linux Tests (dbg)(1)': {
-        'args': [
-          '--test-launcher-print-test-stdio=always',
-        ],
-      },
-      'Linux Tests (dbg)(1)(32)': {
-        'args': [
-          '--test-launcher-print-test-stdio=always',
-        ],
-      },
-    },
-  },
   'services_unittests': {
     'remove_from': [
       # chromium.clang