Consider adding GradleRunner#run() as an unopinionated alternative to build()

[lacasseio]

The methods build() and buildAndFail() and opinionated on the outcome of the build. We should introduce run() which would be unopinionated on the state of the build. Users would have to validate the outcome.

The major reason against this API is there is no real valid reason to execute a Gradle build without expectation. For example, if we just want to execute task :foo, if we don't care about the outcome... would :foo execute successfully or not. Most likely, we would use build() so :foo is executed successfully, to the extent of what success means in the context.

[lacasseio]

There is a good chance we may not want to solve this issue unless we have a real use case.