Partial rebalance of TEST_GROUPs for Travis (#6010)

Summary:
TEST_GROUP=1 has sometimes been timing out but generally taking
45-50 minutes vs. 20-25 for groups 2-4. Beyond the compilation time, tests in
group 1 consist of about 19 minutes of db_test, and 7 minutes of everything
else. This change moves most of that "everything else" to group 2.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6010

Test Plan: Travis for this PR, oncall watch Travis

Differential Revision: D18373536

Pulled By: pdillinger

fbshipit-source-id: 0b3af004c71e4fd6bc01a94dac34cc3079fc9ce1

.travis.yml

@@ -89,13 +89,13 @@ script:
       OPT=-DTRAVIS V=1 ROCKSDBTESTS_END=db_block_cache_test make -j4 all_but_some_tests check_some
       ;;
     1)
-      OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=db_block_cache_test ROCKSDBTESTS_END=full_filter_block_test make -j4 check_some
+      OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=db_block_cache_test ROCKSDBTESTS_END=db_iter_test make -j4 check_some
       ;;
     2)
-      OPT=-DTRAVIS V=1 make -j4 tools && OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=full_filter_block_test ROCKSDBTESTS_END=write_batch_with_index_test make -j4 check_some
+      OPT=-DTRAVIS V=1 make -j4 tools && OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=db_iter_test ROCKSDBTESTS_END=options_file_test make -j4 check_some
       ;;
     3)
-      OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=write_batch_with_index_test ROCKSDBTESTS_END=write_prepared_transaction_test make -j4 check_some
+      OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=options_file_test ROCKSDBTESTS_END=write_prepared_transaction_test make -j4 check_some
       ;;
     4)
       OPT=-DTRAVIS V=1 ROCKSDBTESTS_START=write_prepared_transaction_test make -j4 check_some