Set index_block_restart_interval of kHashSearch to 1 in stress test (#6324)

Summary:
kHashSearch is incompatible with larger than 1 values for index_block_restart_interval. Setting it to 1 in stress tests would avoid confusion about the test parameters.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6324

Differential Revision: D19525669

Pulled By: maysamyabandeh

fbshipit-source-id: fbf3a797e0ebcebb4d32eba3728cf3583906fc8a

tools/db_crashtest.py

@@ -238,6 +238,9 @@ def finalize_and_sanitize(src_params):
     if dest_params["index_type"] == 1 and \
         dest_params.get("prefix_size", 7) == -1:
         dest_params["index_type"] = 0       
+    # kHashSearch is incompatible with index_block_restart_interval > 1
+    if dest_params["index_type"] == 1:
+        dest_params["index_block_restart_interval"] = 1;
     if dest_params.get("atomic_flush", 0) == 1:
         # disable pipelined write when atomic flush is used.
         dest_params["enable_pipelined_write"] = 0