Add '-tryjob' suffix to build name.

We got some errors like
These configs are not tryjob safe:
    link-llvm-next-toolchain
Consider these configs instead:
    link-llvm-next-toolchain-tryjob
when lauching tryjobs to get the image.

This CL fixes that.

BUG=none
TEST=The build name is changed.

Change-Id: I56ef66dfb1071367b78ee8a7335552cdae5a5b44
Reviewed-on: https://chromium-review.googlesource.com/791391
Commit-Ready: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>
diff --git a/buildbot_test_llvm.py b/buildbot_test_llvm.py
index e1b515d..6c39c3a 100755
--- a/buildbot_test_llvm.py
+++ b/buildbot_test_llvm.py
@@ -86,7 +86,7 @@
     self._ce = command_executer.GetCommandExecuter()
     self._l = logger.GetLogger()
     self._compiler = compiler
-    self._build = '%s-%s-toolchain' % (board, compiler)
+    self._build = '%s-%s-toolchain-tryjob' % (board, compiler)
     self._patches = patches.split(',') if patches else []
     self._patches_string = '_'.join(str(p) for p in self._patches)