[gold] Enable time trace profiler in LLVMgold (#94293)

To get the time trace of LTO in the gold plugin, now we can pass the
`time-trace=<time trace file>` as well as
`time-trace-granularity=<granularity>` flags to LLVMgold.

Note that we still have to populate `LTOConfig::TimeTraceEnabled` and
`LTOConfig::TimeTraceGranularity` because ThinLTO backend needs them.