cross-tool protocol: support CLOCK_BOOTTIME

With this CL, the cross-tool protocol supports synchronization
based on timestamps with type CLOCK_BOOTTIME.
Previously only CLOCK_REALTIME timestamps where supported.
CLOCK_BOOTTIME is needed for more accurate synchronization with Perfetto.

Bug: 332833838
Test: npm run test:presubmit && npm run test:e2e
Change-Id: I7e9d97997382ad345b37b93116d96409e63f80cc
10 files changed