Add a new "debug" status message, use for stats

This will allow the android build to always set "-d stats", and redirect
the output to a verbose log file for later analysis.

Test: NINJA_ARGS="-d stats" m nothing  (without changes to soong_ui -- prints to stdout)
Test: m nothing   (with changes to soong_ui, see in verbose.log.gz)
Change-Id: Idc6a9964970f8bc457b4c72cb177998d67149e4a
10 files changed