Automate capture of build scan dumps for external sharing

Sometimes it is the case that a user may run the Build Validation Scripts and want to share the results with Gradle to investigate. Currently, a user must run the experiments, then manually go acquire the two build scan dumps after the experiment completes. It would be ideal if there were an easy, slightly more automated mechanism for users to do this.

Start by inspecting the build validation scripts and the workflow that runs experiments and leaves the two build scan dumps for manual acquisition. Determine the intended automated collection or sharing flow; done means users can obtain the relevant dumps without manually locating them after an experiment.

Written by the indexing model from the issue text.