Avoid running the launch script tests unnecessarily #28164
Description
At the moment, the test app used by spring-boot-launch-script-tests depends on spring-boot-starter-web. This means that if anything changes in spring-boot or spring-boot-autoconfigure we'll get a cache miss and the tests will be run again. This is sub-optimal as all we're really interested in testing is the launch script which is part of spring-boot-loader-tools and it being prepended to the jar file.
We can improve the situation by minimising the dependencies of the test app.