Add support for core.memory.GC.ProfileStats to ocean.application.components.GCStats

[leandro-lucarella-sociomantic]

dmd 2.085 introduced a new API to get GC timing and collection info: core.memory.GC.ProfileStats.

We should make use of it (when available) in ocean.application.components.GCStats.

[joseph-wakeling-frequenz]

FYI @leandro-lucarella-sociomantic, I have raised the question with W&A about whether druntime can also support providing stomping prevention stats. I'll give you a shout if there's any progress with that ;-)