[ChromeDriver] Disable failing tests on Mac platform

The following Java tests are failing on Waterfall on Mac platform:

WindowTest.testCanMaximizeTheWindowFromFrame
WindowTest.testCanMaximizeTheWindowFromIframe
WindowTest.testCanMaximizeTheWindow

Disabling these tests.

Bug: chromedriver:2748
Change-Id: I611f95abe1b1f02e47d4ea19e1c64ba5f5a74781
Reviewed-on: https://chromium-review.googlesource.com/c/1427925Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Artur Khachatryan <khachatryan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624976}

chrome/test/chromedriver/test/test_expectations

@@ -48,6 +48,10 @@ _OS_NEGATIVE_FILTER['mac'] = [
     'WindowTest.canFullscreenTheWindowFromIframe',
     'WindowTest.testSetsTheSizeOfTheCurrentWindow',
     'BasicMouseInterfaceTest.testMovingMouseByRelativeOffset',
+    # https://bugs.chromium.org/p/chromedriver/issues/detail?id=2748
+    'WindowTest.testCanMaximizeTheWindowFromFrame',
+    'WindowTest.testCanMaximizeTheWindowFromIframe',
+    'WindowTest.testCanMaximizeTheWindow',
 ]
 
 _SPECIFIC_OS_REVISION_NEGATIVE_FILTER = {}