Improve sharding parameters for linux_chromium_tsan_rel_ng.

Each of the test suites modified had a per-shard runtime of more than 10
minutes. This CL updates all of them to have expected runtimes of 10 minutes,
while still keeping overhead below 10%.

Timings come from:
https://ci.chromium.org/p/chromium/builders/try/linux_chromium_tsan_rel_ng/430164

Pre-patch runtimes, timings from
https://ci.chromium.org/p/chromium/builders/try/linux_chromium_tsan_rel_ng/430164
interactive_ui_tests [31 minutes, 35 second overhead]
content_browsertests [24 minutes, 35 second overhead]
cc_unittests [21 minutes, 13 second overhead]
components_unittests [17 minutes, 41 second overhead]
webkit_unit_tests [17 minutes, 22 second overhead]


Bug: 1028289
Change-Id: I3254bdb3f26e07a5eec77da4633cd6e0ea1d8311
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1937574
Commit-Queue: Erik Chen <erikchen@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719377}

testing/buildbot/chromium.memory.json

@@ -11361,7 +11361,8 @@
             {
               "os": "Ubuntu-16.04"
             }
-          ]
+          ],
+          "shards": 2
         },
         "test": "blink_unittests"
       },
@@ -11470,7 +11471,8 @@
             {
               "os": "Ubuntu-16.04"
             }
-          ]
+          ],
+          "shards": 3
         },
         "test": "cc_unittests"
       },
@@ -11560,7 +11562,8 @@
             {
               "os": "Ubuntu-16.04"
             }
-          ]
+          ],
+          "shards": 2
         },
         "test": "components_unittests"
       },
@@ -11597,7 +11600,7 @@
               "os": "Ubuntu-16.04"
             }
           ],
-          "shards": 6
+          "shards": 15
         },
         "test": "content_browsertests"
       },
@@ -12031,7 +12034,7 @@
               "os": "Ubuntu-16.04"
             }
           ],
-          "shards": 6
+          "shards": 20
         },
         "test": "interactive_ui_tests"
       },

testing/buildbot/test_suite_exceptions.pyl

@@ -294,6 +294,15 @@
       },
     },
   },
+  'cc_unittests': {
+    'modifications': {
+      'Linux TSan Tests': {
+        'swarming': {
+          'shards': 3,
+        },
+      },
+    },
+  },
   'checkbins': {
     'remove_from': [
       'linux-archive-dbg',
@@ -424,6 +433,11 @@
           'shards': 5,
         },
       },
+      'Linux TSan Tests': {
+        'swarming': {
+          'shards': 2,
+        },
+      },
     },
   },
   'content_browsertests': {
@@ -500,6 +514,11 @@
           'idempotent': False, # https://crbug.com/1013093
         },
       },
+      'Linux TSan Tests': {
+        'swarming': {
+          'shards': 15,
+        },
+      },
       'linux-chromeos-rel': {
         'swarming': {
           'shards': 3,
@@ -832,7 +851,7 @@
       'Linux TSan Tests': {
         # These are slow on the TSan bots for some reason, crbug.com/794372
         'swarming': {
-          'shards': 6,
+          'shards': 20,
         },
       },
       'Linux ChromiumOS MSan Tests': {
@@ -2201,6 +2220,11 @@
           'shards': 5,
         },
       },
+      'Linux TSan Tests': {
+        'swarming': {
+          'shards': 2,
+        },
+      },
       'Marshmallow 64 bit Tester': {
         # Increase timeout. See https://crbug.com/847229.
         'swarming': {