VM: Clear all *_to_retain maps when resetting the precompiler state
VM: Clear all *_to_retain maps when resetting the precompiler state

We often do work when adding entries to these maps but when entries already
exist we skip the work. When running the precompiler multiple times we should
clear the maps to ensure we always to the necessary work.

R=vegorov@google.com

Review-Url: https://codereview.chromium.org/2592083002 .

dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk