Bug 1446954: Remove support for running tests on automation without stylo configurations. r=froydnj

You can still run them on a --disable-stylo build, as long as that works
(presumably not for long).

I think I haven't missed anything, but please double-check.

MozReview-Commit-ID: 3BIAEjgTLo5

taskcluster/taskgraph/try_option_syntax.py

@@ -98,7 +98,6 @@ UNITTEST_ALIASES = {
     'reftest-no-accel': alias_matches(r'^(plain-)?reftest-no-accel.*$'),
     'reftests': alias_matches(r'^(plain-)?reftest.*$'),
     'reftests-e10s': alias_matches(r'^(plain-)?reftest-e10s.*$'),
-    'reftest-stylo': alias_matches(r'^(plain-)?reftest-stylo.*$'),
     'reftest-gpu': alias_matches(r'^(plain-)?reftest-gpu.*$'),
     'robocop': alias_prefix('robocop'),
     'web-platform-test': alias_prefix('web-platform-tests'),
@@ -126,13 +125,11 @@ UNITTEST_PLATFORM_PRETTY_NAMES = {
         'linux32',
         'linux64',
         'linux64-asan',
-        'linux64-stylo-disabled',
         'linux64-stylo-sequential'
     ],
     'x64': [
         'linux64',
         'linux64-asan',
-        'linux64-stylo-disabled',
         'linux64-stylo-sequential'
     ],
     'Android 4.3': ['android-4.3-arm7-api-16'],