vibratorservice: Fix broken benchmarks

Fixes an issue with the benchmarks, where they would skip unsupported
situations by early returning without reaching the measure loop and
without notifying the framework.

The framework would then retry the exact same scenario indefinitely.

To fix, makes sure every early return also calls SkipWithMessage.

Fixes: 279134938
Test: adb shell /tmp/VibratorHalControllerBenchmarks --v=2
Change-Id: If7f92816133bf3d03a5915b6f077eb961d55cf75