test-bdiff: move import inside the function to avoid test failure
test-check-module-imports.t fails on some systems where the path of home
directories is different than sys.prefix and sys.exec_prefix.
Importing silenttestrunner will help avoiding that failure.
profiling: add statprof support for Chrome trace viewer rendering
We synthesize function call begin/end events from snapshots, and
try (configurably) to eliminate "noisy" stack frames.
Example invocation:
hg --config profiling.output=$HOME/Desktop/clone.json \
--config profiling.statformat=chrome \
--profile clone https://www.mercurial-scm.org/repo/hg