Run performance test for metrics

Before this patch, performance tests ran together with unit and
integration with `--coverage` flag. Coverage analysis cropped the
result of performance tests to 10-15 times. For metrics integration
it resulted in timeout errors and drop of performance which is not
reproduces with coverage disabled. Moreover, before this patch log
capture was disabled and performance tests did not displayed any
results after run.

After this patch, `make -C build coverage` will run lightweight
version of performance test. `make -C build performance` will run real
performance tests.

This path also reworks current performance test. It adds new cases to
compare module performance with or without statistics, statistic
wrappers and compare different metrics drivers and reports new info:
average call time and max call time.

Performance test result: overhead is 3-7% in case of `local` driver and
5-15% in case of `metrics` driver, up to 20% for `metrics` with
quantiles. Based on several runs on HP ProBook 440 G7 i7/16Gb/256SSD.

Closes #233, follows up #224

Author: DifferentialOrange

README.md

@@ -620,6 +620,8 @@ crud.enable_stats({ driver = 'metrics', quantiles = true })
 -- Use simple local collectors.
 crud.enable_stats({ driver = 'local' })
 ```
+Performance overhead is 3-7% in case of `local` driver and
+5-15% in case of `metrics` driver, up to 20% for `metrics` with quantiles.
 
 Format is as follows.
 ```

test/entrypoint/srv_ddl.lua

@@ -90,6 +90,12 @@ package.preload['customers-storage'] = function()
                 },
             }
 
+            local customers_id_schema = table.deepcopy(customers_schema)
+            customers_id_schema.sharding_key = {'id'}
+            table.insert(customers_id_schema.indexes, primary_index_id)
+            table.insert(customers_id_schema.indexes, bucket_id_index)
+            table.insert(customers_id_schema.indexes, age_index)
+
             local customers_name_key_schema = table.deepcopy(customers_schema)
             customers_name_key_schema.sharding_key = {'name'}
             table.insert(customers_name_key_schema.indexes, primary_index)
@@ -133,6 +139,7 @@ package.preload['customers-storage'] = function()
 
             local schema = {
                 spaces = {
+                    customers = customers_id_schema,
                     customers_name_key = customers_name_key_schema,
                     customers_name_key_uniq_index = customers_name_key_uniq_index_schema,
                     customers_name_key_non_uniq_index = customers_name_key_non_uniq_index_schema,
@@ -166,8 +173,8 @@ local ok, err = errors.pcall('CartridgeCfgError', cartridge.cfg, {
         'customers-storage',
         'cartridge.roles.crud-router',
         'cartridge.roles.crud-storage',
-    },
-})
+    }}, { readahead = 20 * 1024 * 1024 }
+)
 
 if not ok then
     log.error('%s', err)