Remove non UTF-8 chars from debug output

The debug output might contain non UTF-8 chars. Theses bad characters
are not compatible with the debug toolbar. As a result the debug
toolbar disappears. Non UTF-8 chars are being produced by the database
log that prints out binary fields for example.

Bug: 48951
Change-Id: I42f7a5c913b378c05b68970646c75894ca068ed9
Merge "Remove non UTF-8 chars from debug output"