Disable minidump tests on Linux

Disables the Telemetry minidump symbolization tests on Linux, as they
are currently flaking pretty badly.

TBR=johnchen@chromium.org

Bug: 1108432
Change-Id: I3fab14b82de7440eff534169cf028d324d6f37c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2333667Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794208}

tools/perf/core/minidump_unittest.py

@@ -35,6 +35,7 @@ class BrowserMinidumpTest(tab_test_case.TabTestCase):
   # still read-only, so skip the test in that case.
   @decorators.Disabled(
       'chromeos-local',
+      'linux',  # https://crbug.com/1108432
       'win'  # https://crbug.com/1084931
   )
   def testSymbolizeMinidump(self):
@@ -80,6 +81,7 @@ class BrowserMinidumpTest(tab_test_case.TabTestCase):
   # still read-only, so skip the test in that case.
   @decorators.Disabled(
       'chromeos-local',
+      'linux',  # https://crbug.com/1108432
       'win'  # https://crbug.com/1084931
   )
   def testMultipleCrashMinidumps(self):