fix: fix the pebble config of level option

[flywukong]

Description

Although pebble is initialized to level 7 by default, the configuration of level options does not take effect because the level option slices has no explicit initialization.

The option file content of the chain db is as follows after fixed which meet expected option (block size is 32kB, indexBlock size is 256KB , and enable bloom filter) :

[root@tf_nodereal_dev_bsc_new_feature_testing1_ec2 chaindata]# tail -40  OPTIONS-000013 

[Level "3"]
  block_restart_interval=16
  block_size=32768
  block_size_threshold=90
  compression=Snappy
  filter_policy=rocksdb.BuiltinBloomFilter
  filter_type=table
  index_block_size=262144
  target_file_size=16777216

[Level "4"]
  block_restart_interval=16
  block_size=32768
  block_size_threshold=90
  compression=Snappy
  filter_policy=rocksdb.BuiltinBloomFilter
  filter_type=table
  index_block_size=262144
  target_file_size=33554432

[Level "5"]
  block_restart_interval=16
  block_size=32768
  block_size_threshold=90
  compression=Snappy
  filter_policy=rocksdb.BuiltinBloomFilter
  filter_type=table
  index_block_size=262144
  target_file_size=67108864

[Level "6"]
  block_restart_interval=16
  block_size=32768
  block_size_threshold=90
  compression=Snappy
  filter_policy=rocksdb.BuiltinBloomFilter
  filter_type=table
  index_block_size=262144
  target_file_size=134217728

Rationale

performance is better after fixed
(block height 3430w+ , 500M 3000iops disk and 16 core machine)

Example

add an example CLI or API response...

Changes

Notable changes:

• add each change in a bullet point here
• ...

[RenRick]

LGTM

[fynnss]

LGTM