MariaRocks port: add have_rocksdb.opt which enables MyRocks' plugins

A number of tests used to fail due to just not being able to
access MyRocks' I_S plugins:
cons_snapshot_repeatable_read
-drop_table3
-index_file_map
-index_key_block_size
-issue100_delete
-truncate_table3

mysql-test/include/have_rocksdb.opt

+--loose-enable-rocksdb --loose-enable-rocksdb_global_info --loose-enable-rocksdb_ddl --loose-enable-rocksdb_cf_options --loose-enable_rocksdb_perf_context --loose-enable-rocksdb_index_file_map --loose-enable-rocksdb_dbstats