orcprofile: Implement Windows high-resolution timestamp for MSVC
Hi!
This MR implements Orc's "timestamping" feature to allow benchmarking on MSVC builds. The intention is to rely on Windows APIs solely, allowing benchmarks to run irrespective of the underlying platform; currently, benchmarks only work on MSVC x86 builds, or on MinGW builds (which do implement clock_gettime
).
It is split off !111 (merged) in order to allow easier review.