Create the wificell_preflight pool.

More new devices are showing up that can only be run against ToT.
Creating a new pool and making sure only ToT tests are run against it.

TEST=None
BUG=chromium:360210

Change-Id: I4b485ca3c32e210e7ed3260d4b79708a558f291f
Reviewed-on: https://chromium-review.googlesource.com/193676
Tested-by: Kris Rambish <krisr@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Kris Rambish <krisr@chromium.org>
diff --git a/suite_scheduler.ini b/suite_scheduler.ini
index 0bba159..47569e1 100644
--- a/suite_scheduler.ini
+++ b/suite_scheduler.ini
@@ -261,6 +261,12 @@
 branch_specs: >=R29
 pool: wificell
 
+[WiFi_MatFuncDaily_Preflight]
+run_on: nightly
+suite: wifi_matfunc
+branch_specs: >=R36
+pool: wificell_preflight
+
 [WiFi_Perf]
 run_on: nightly
 suite: wifi_perf