Extend dumpstate.dry_run restrictions

Ensure that dumpstate runs quicker in dry run mode by
only printing the dumpsys headers/footers, and not
adding ANRs or tombstones to the bugreport.

Test: adb shell setprop dumpstate.dry_run true; adb bugreport
Bug: 196864582
Change-Id: Ib43a5e55ea05db368c9b84a3b9f32a263b9224bd