Remove unused test configs for CFI bots on the FYI waterfall.

These bots used to be on FYI, but they're on the clang waterfall now
(and also listed for that waterfall in waterfalls.pyl)

Bug: 843511
Change-Id: I5ee01813e2701e1346edb05bbb5d3bae723b9b96
Reviewed-on: https://chromium-review.googlesource.com/1093555
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565722}

testing/buildbot/waterfalls.pyl

@@ -2040,16 +2040,6 @@
         'os_type': 'android',
         'skip_output_links': True,
       },
-      'CFI Linux (icall)': {
-        'test_suites': {
-          'gtest_tests': 'chromium_linux_and_gl_gtests',
-        },
-      },
-      'CFI Linux ToT': {
-        'test_suites': {
-          'gtest_tests': 'chromium_linux_and_gl_gtests',
-        },
-      },
       'Chromium Mac 10.13': {
         'test_suites': {
           'gtest_tests': 'chromium_mac_fyi_gtests',