TraceUtils updates, new helper for runnables

Modify TraceUtils' traceSection to use traceBegin instead of
beginSection because beginSection will crash at run-time if the string
is longer than 127 chars.

Also, guard against StringBuilder GC garbage while tracing.

Test: manual
Bug: 257075630
Change-Id: I74cb5687a206f5d7ab8eb570cf24715d7e671df1