simpleperf: start simpleperf boot-record at zygote-start stage.

This is a little earlier than boot stage. It starts simpleperf
boot-record right after zygote is started.

Bug: 214731005
Test: run simpleperf manually
Change-Id: Id4f8541373cf5ee173cc7ad006331d2ce91d3a1d
1 file changed