[ruby/sinatra] Remove some test variations

Don't run every permutation as there isn't a lot of variation.
Limit to running:
- Puma with MySQL (the default)
- Puma with Postgres
- Unicorn with Postgres
- Passenger with Postgres

This remove the following variations which were slower that their
Postgres alternative:
- Unicorn with MySQL
- Passenger with MySQL

Author: p8

frameworks/Ruby/sinatra/benchmark_config.json

@@ -44,28 +44,6 @@
         "versus": "rack-postgres-puma-mri",
         "notes": ""
       },
-      "passenger-mri": {
-        "json_url": "/json",
-        "db_url": "/db",
-        "query_url": "/queries?queries=",
-        "fortune_url": "/fortunes",
-        "update_url": "/updates?queries=",
-        "plaintext_url": "/plaintext",
-        "port": 8080,
-        "approach": "Realistic",
-        "classification": "Micro",
-        "database": "MySQL",
-        "framework": "sinatra",
-        "language": "Ruby",
-        "orm": "Full",
-        "platform": "Rack",
-        "webserver": "Passenger",
-        "os": "Linux",
-        "database_os": "Linux",
-        "display_name": "sinatra-passenger-mri",
-        "versus": "rack-passenger-mri",
-        "notes": ""
-      },
       "postgres-passenger-mri": {
         "db_url": "/db",
         "query_url": "/queries?queries=",
@@ -86,28 +64,6 @@
         "versus": "rack-postgres-passenger-mri",
         "notes": ""
       },
-      "unicorn-mri": {
-        "json_url": "/json",
-        "db_url": "/db",
-        "query_url": "/queries?queries=",
-        "fortune_url": "/fortunes",
-        "update_url": "/updates?queries=",
-        "plaintext_url": "/plaintext",
-        "port": 8080,
-        "approach": "Realistic",
-        "classification": "Micro",
-        "database": "MySQL",
-        "framework": "sinatra",
-        "language": "Ruby",
-        "orm": "Full",
-        "platform": "Rack",
-        "webserver": "Unicorn",
-        "os": "Linux",
-        "database_os": "Linux",
-        "display_name": "sinatra-unicorn-mri",
-        "versus": "rack-unicorn-mri",
-        "notes": ""
-      },
       "postgres-unicorn-mri": {
         "db_url": "/db",
         "query_url": "/queries?queries=",