[ dartdev ] Disable dartdev snapshot generation for runtime build
[ dartdev ] Disable dartdev snapshot generation for runtime build

Change-Id: Ib0b9917543e2d9d82431b78a9d372ba2cf2ed10e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/146687
Reviewed-by: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk