Run sky tests more parallelized.

sky/tools/webkitpy/layout_tests/port/base.py

Index: sky/tools/webkitpy/layout_tests/port/base.py
diff --git a/sky/tools/webkitpy/layout_tests/port/base.py b/sky/tools/webkitpy/layout_tests/port/base.py
index 9227ac66ad8f23eae644be168942ec75b701cf6c..efcfa6f78f20682280759d98a9baac18b0c02bf6 100644
--- a/sky/tools/webkitpy/layout_tests/port/base.py
+++ b/sky/tools/webkitpy/layout_tests/port/base.py
@@ -270,10 +270,7 @@ class Port(object):
 
     def default_child_processes(self):
         """Return the number of drivers to use for this port."""
-        # FIXME: See if we can reduce the denominator here without causing timeouts.
-        # Maybe we need to run one sky_shell process and multiple sky_viewers
-        # instead of multiple sky_shells
-        return int(math.ceil(float(self._executive.cpu_count()) / 4))
+        return self._executive.cpu_count()
 
     def default_max_locked_shards(self):
         """Return the number of "locked" shards to run in parallel (like the http tests)."""