[build][dart] Add dart_remote_test template.

Adds a new dart_remote_test template which sets up a test that
requires connecting to a target from the host machine.

TEST=Manual w/ //topaz/examples/test/driver_example_mod and run-dart-action.py

Change-Id: I6e4a188e4bf8ecfe0b1069dc3d84be217410e9bc
2 files changed