Fix gson usage with R8 full mode

Ensure the appropriate signatures are retained for ClockRegistry's gson
usage when R8 full mode is enabled.

Bug: 215530220
Bug: 229771520
Test: m + boot tests
Change-Id: I824b870a355a4cfea04e55d5648a6c441ab446d3
(cherry picked from commit 994594ba6f490c1fcb2035ba79be53246424335c)
Merged-In: I824b870a355a4cfea04e55d5648a6c441ab446d3
2 files changed