Fixed some sign compare errors in newly added TraceStats tests
Fixed some sign compare errors in newly added TraceStats tests

Bug: 76169489
Change-Id: I245ed6090a86f20fcf586be5f00f7fcd45c4737c

google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto