Enhance slow-query log output

- Show DB filename
- Print result for execute-for-string and for-long to debug PRAGMA
related issues.

Bug: 112175067
Test: booted with "setprop db.log.slow_query_threshold 0" and
"setprop db.log.detailed 1"

Change-Id: I2a4093755b3fe7a6ae2c0fad93f8224da834062e