move the Android emulator launching code over to using the flutter_tools implementation

See https://github.com/flutter/flutter/issues/13379; we can launch Android emulators in IntelliJ, but we're using a separate code path from flutter_tools. We should move over to the flutter_tools based impl.

Start by reading the linked Flutter issue and tracing the existing Android emulator launch path in the IntelliJ plugin. Compare it with the flutter_tools-based implementation and identify the integration points that must change. Done means IntelliJ launches Android emulators through the flutter_tools implementation with existing behavior preserved; the payload names no files or tests.

Written by the indexing model from the issue text.