[llvm] Changing TimeProfiler.cpp clock from microseconds to nanoseconds (PR #68096)

[via llvm-commits]

fel-cab wrote:

> So, this allows to include nanoseconds events but it still will list their time in microseconds, correct? Should there be a switch?

Yes, it list the time still in microseconds, to use the Perfetto/chronium defaults. The switch would be better than leave it fixed.

https://github.com/llvm/llvm-project/pull/68096