Change Windows / OSX to use 8 cores

Author: pkch

mypy/waiter.py

@@ -122,7 +122,7 @@ def __init__(self, limit: int = 0, *, verbosity: int = 0, xfail: List[str] = [])
             try:
                 sched_getaffinity = os.sched_getaffinity
             except AttributeError:
-                limit = 2
+                limit = 8
             else:
                 # Note: only count CPUs we are allowed to use. It is a
                 # major mistake to count *all* CPUs on the machine.