Bump third_party/perfetto/repo from `b9aca8f` to `b4c1dfa` #2433

Job	Run time
Build on Darwin (clang, simulated)	8m 27s
Build on Linux (fake, gcc_release, clang, simulated)	2m 24s
Build on Linux (coverage)	13m 49s
Build on Linux (python_lib)	2m 9s
Build on Linux (python lighting-app)	5m 56s
Build on Linux (gcc_debug)	3m 11s
	35m 56s

Provide feedback