CHROMIUM: disable pkg_pretend phase

Gentoo uses this for basic functionality & state checks, none of which
matter to CrOS, or will never pass (like kernel or free disk space).
Disable running of these phases entirely since they're a blocking phase
that prevents actual install of packages until things finish download.

BUG=None
TEST=CQ passes

Change-Id: I90cbbaeb682a67cde0fbc0418d37cd0235a20a9b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/portage_tool/+/3388881
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/lib/_emerge/Scheduler.py b/lib/_emerge/Scheduler.py
index b21e1fc..6156985 100644
--- a/lib/_emerge/Scheduler.py
+++ b/lib/_emerge/Scheduler.py
@@ -776,6 +776,10 @@
 		--jobs).
 		"""
 
+		# The vast majority of checks are kernel configs or disk/memory sizes.
+		# We don't need/care about those in CrOS.
+		return os.EX_OK
+
 		failures = 0
 		sched_iface = loop = asyncio._wrap_loop(loop or self._sched_iface)
 		did_work = False