refs: Split up acceptance tests again. (#12705)

Percy was holding us back from doing this sooner, it has since been removed.

Co-authored-by: Billy Vong <billy@sentry.io>

.travis.yml

@@ -198,8 +198,14 @@ matrix:
       env: TEST_SUITE=postgres DB=postgres TOTAL_TEST_GROUPS=2 TEST_GROUP=1 MIGRATIONS_TEST_MIGRATE=1
 
     - <<: *acceptance_default
-      name: 'Acceptance'
-      env: TEST_SUITE=acceptance USE_SNUBA=1
+      name: 'Acceptance (1/3)'
+      env: TEST_SUITE=acceptance USE_SNUBA=1 TOTAL_TEST_GROUPS=3 TEST_GROUP=0
+    - <<: *acceptance_default
+      name: 'Acceptance (2/3)'
+      env: TEST_SUITE=acceptance USE_SNUBA=1 TOTAL_TEST_GROUPS=3 TEST_GROUP=1
+    - <<: *acceptance_default
+      name: 'Acceptance (3/3)'
+      env: TEST_SUITE=acceptance USE_SNUBA=1 TOTAL_TEST_GROUPS=3 TEST_GROUP=2
 
     - <<: *acceptance_default
       name: 'Plugins'