Reland "Webkit layout test runner: Add option for zero tests executed"

This reverts commit dea64670de644d174b4a548022b2101ba0a59154.

Reason for revert: Re-landing CL

Original change's description:
> Revert "Webkit layout test runner: Add option for zero tests executed"
> 
> This reverts commit e3ce42822c4ebe5669dcc33ad9c3b8c77ed1dab1.
> 
> Reason for revert: Causing failures on webkit linux trusty leak bot https://ci.chromium.org/buildbot/chromium.webkit/WebKit%20Linux%20Trusty%20Leak/17952
> 
> Original change's description:
> > Webkit layout test runner: Add option for zero tests executed
> > 
> > Adds --zero-tests-executed-ok, which makes the layout test runner exit
> > with an ok status if zero tests are executed. This is important for
> > re-running layout tests without patch, which we do on tryservers to
> > check if the test was being flaky.
> > 
> > Bug: 533481
> > Change-Id: I7d6bcd805b99818fdf82ecb88e71863ff72b72e7
> > Reviewed-on: https://chromium-review.googlesource.com/1018590
> > Reviewed-by: Quinten Yearsley <[email protected]>
> > Reviewed-by: Jeff Carpenter <[email protected]>
> > Reviewed-by: Robert Ma <[email protected]>
> > Reviewed-by: Dirk Pranke <[email protected]>
> > Commit-Queue: Stephen Martinis <[email protected]>
> > Cr-Commit-Position: refs/heads/master@{#552426}
> 
> [email protected],[email protected],[email protected],[email protected],[email protected]
> 
> Change-Id: Ibfe5f1bc3c02354a975d058c5d6338d0762c6e34
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 533481
> Reviewed-on: https://chromium-review.googlesource.com/1022555
> Reviewed-by: Jesse Doherty <[email protected]>
> Commit-Queue: Jesse Doherty <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#552470}

[email protected],[email protected],[email protected],[email protected],[email protected],[email protected]

Change-Id: I76b1a0fdd188aa174eeb546d548aa4e4a751e4f5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 533481
Reviewed-on: https://chromium-review.googlesource.com/1022556
Commit-Queue: Stephen Martinis <[email protected]>
Reviewed-by: Robert Ma <[email protected]>
Reviewed-by: Jeff Carpenter <[email protected]>
Reviewed-by: Stephen Martinis <[email protected]>
Cr-Commit-Position: refs/heads/master@{#552795}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index 9b5a178a..845dcc5 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -3478,6 +3478,9 @@
       # TODO(dpranke): Clean up all of the unneeded exceptions on
       # chromium.webkit.
       'WebKit Linux Trusty': {
+        'args': [
+          '--zero-tests-executed-ok',
+        ],
         'swarming': {
           'dimension_sets': [
             {
@@ -3489,6 +3492,7 @@
       'WebKit Linux Trusty (dbg)': {
         'args': [
           '--debug',
+          '--zero-tests-executed-ok',
         ],
         'swarming': {
           'dimension_sets': [
@@ -3506,6 +3510,7 @@
           '--time-out-ms',
           '48000',
           '--enable-sanitizer',
+          '--zero-tests-executed-ok',
         ],
         'swarming': {
           'dimension_sets': [
@@ -3523,6 +3528,7 @@
           '--time-out-ms',
           '48000',
           '--enable-leak-detection',
+          '--zero-tests-executed-ok',
         ],
         'swarming': {
           'dimension_sets': [
@@ -3540,6 +3546,7 @@
           '--time-out-ms',
           '66000',
           '--enable-sanitizer',
+          '--zero-tests-executed-ok',
         ],
         'swarming': {
           'dimension_sets': [
@@ -3559,6 +3566,9 @@
         ],
       },
       'WebKit Win10': {
+        'args': [
+          '--zero-tests-executed-ok',
+        ],
         'swarming': {
           'dimension_sets': [
             {
@@ -3568,6 +3578,9 @@
         },
       },
       'WebKit Win7': {
+        'args': [
+          '--zero-tests-executed-ok',
+        ],
         'swarming': {
           'dimension_sets': [
             {
@@ -3577,6 +3590,9 @@
         },
       },
       'WebKit Win7 (dbg)': {
+        'args': [
+          '--zero-tests-executed-ok',
+        ],
         'swarming': {
           'dimension_sets': [
             {