Start testing compiler-rt with llvm-next.

We want to test compiler-rt performance and stability.
So start testing llvm-next with compiler-rt as default using CL
513590.

BUG=chromium:705071
TEST=buildbot runs with CL 513590 are fine for daisy, squawks, elm and
peppy.

Change-Id: Ic43ef238c7fce0cb88caabab7e6a32b1940cb860
Reviewed-on: https://chromium-review.googlesource.com/514302
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Trybot-Ready: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>
diff --git a/buildbot_test_toolchains.py b/buildbot_test_toolchains.py
index c03c009..06707be 100755
--- a/buildbot_test_toolchains.py
+++ b/buildbot_test_toolchains.py
@@ -29,7 +29,7 @@
 from cros_utils import buildbot_utils
 
 # CL that uses LLVM-Next to build the images (includes chrome).
-USE_LLVM_NEXT_PATCH = '419149'
+USE_LLVM_NEXT_PATCH = '513590'
 
 CROSTC_ROOT = '/usr/local/google/crostc'
 ROLE_ACCOUNT = 'mobiletc-prebuild'