macOS: Also consider compressed pages as usable. (#89)

It should be possible to put them in swap relatively cheaply.

Author: maleadt

src/ParallelTestRunner.jl

@@ -371,7 +371,7 @@ function available_memory()
 
 	page_size = Int(@ccall sysconf(29::UInt32)::UInt32)
 
-	return (Int(vms[].free_count) + Int(vms[].inactive_count) + Int(vms[].purgeable_count)) * page_size
+	return (Int(vms[].free_count) + Int(vms[].inactive_count) + Int(vms[].purgeable_count) + Int(vms[].compressor_page_count)) * page_size
 end
 
 else