[4.0] Only return wasm config settings if configurable wasm limits enabled

[heifner]

The wasm config settings returned by /v1/chain/get_consensus_parameters are only valid if the protocol feature CONFIGURABLE_WASM_LIMITS2 is enabled. Only return "wasm_config" if protocol feature CONFIGURABLE_WASM_LIMITS2 is enabled.

With protocol activated:

./cleos get consensus_parameters
{
  "chain_config": {
    "max_block_net_usage": 1048576,
    "target_block_net_usage_pct": 1000,
    "max_transaction_net_usage": 524288,
    "base_per_transaction_net_usage": 12,
    "net_usage_leeway": 500,
    "context_free_discount_net_usage_num": 20,
    "context_free_discount_net_usage_den": 100,
    "max_block_cpu_usage": 500000,
    "target_block_cpu_usage_pct": 1000,
    "max_transaction_cpu_usage": 475000,
    "min_transaction_cpu_usage": 100,
    "max_transaction_lifetime": 3600,
    "deferred_trx_expiration_window": 600,
    "max_transaction_delay": 3888000,
    "max_inline_action_size": 524288,
    "max_inline_action_depth": 4,
    "max_authority_depth": 6,
    "max_action_return_value_size": 256
  },
  "wasm_config": {
    "max_mutable_global_bytes": 1024,
    "max_table_elements": 1024,
    "max_section_elements": 8192,
    "max_linear_memory_init": 65536,
    "max_func_local_bytes": 8192,
    "max_nested_structures": 1024,
    "max_symbol_bytes": 8192,
    "max_module_bytes": 20971520,
    "max_code_bytes": 20971520,
    "max_pages": 528,
    "max_call_depth": 251
  }
}

Without protocol activated:

./cleos get consensus_parameters
{
  "chain_config": {
    "max_block_net_usage": 1048576,
    "target_block_net_usage_pct": 1000,
    "max_transaction_net_usage": 524288,
    "base_per_transaction_net_usage": 12,
    "net_usage_leeway": 500,
    "context_free_discount_net_usage_num": 20,
    "context_free_discount_net_usage_den": 100,
    "max_block_cpu_usage": 200000,
    "target_block_cpu_usage_pct": 2500,
    "max_transaction_cpu_usage": 150000,
    "min_transaction_cpu_usage": 100,
    "max_transaction_lifetime": 3600,
    "deferred_trx_expiration_window": 600,
    "max_transaction_delay": 3888000,
    "max_inline_action_size": 524287,
    "max_inline_action_depth": 10,
    "max_authority_depth": 10,
    "max_action_return_value_size": 256
  }
}

Resolves #1660