Enable mmap_stats GME probe

GITLAB_METRICS_EXPORTER_VERSION

-f2d7e32cb5e3d8886a2bac5da2703b31f6a38d88
+65bbfa0b62518691961de096e4a27d7c76307b7c

metrics_server/metrics_server.rb

@@ -45,7 +45,7 @@ def spawn(target, metrics_dir:, **options)
       env = {
         'GOGC' => '10', # Set Go GC heap goal to 10% to curb memory growth.
         'GME_MMAP_METRICS_DIR' => metrics_dir.to_s,
-        'GME_PROBES' => 'self,mmap',
+        'GME_PROBES' => 'self,mmap,mmap_stats',
         'GME_SERVER_HOST' => settings['address'],
         'GME_SERVER_PORT' => settings['port'].to_s
       }

spec/metrics_server/metrics_server_spec.rb

@@ -120,7 +120,7 @@
             {
               'GOGC' => '10',
               'GME_MMAP_METRICS_DIR' => metrics_dir,
-              'GME_PROBES' => 'self,mmap',
+              'GME_PROBES' => 'self,mmap,mmap_stats',
               'GME_SERVER_HOST' => 'localhost',
               'GME_SERVER_PORT' => expected_port,
               'GME_LOG_LEVEL' => 'quiet'