Increase build parallelism for LUCI linux_chromium_rel_ng trybot

I increased ninja -j for buildbot from 50 to 150 in crrev.com/877743
But this increase is not applied to LUCI bot.
Let me enable high build parallelism for LUCI also.

Bug: 731558
Change-Id: Ibd9ece5954142a67a1632b3d4a4a391e4d6f7805
Reviewed-on: https://chromium-review.googlesource.com/954766
Commit-Queue: Takuto Ikuta <tikuta@google.com>
Reviewed-by: Erik Staab <estaab@chromium.org>
Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542003}

infra/config/global/cr-buildbucket.cfg

@@ -77,6 +77,17 @@ builder_mixins {
   }
 }
 
+# This is for tryservers becoming slow and critical path of patch landing.
+builder_mixins {
+  name: "goma-j150"
+  recipe {
+    properties_j: <<END
+    $build/goma: {
+      "jobs": 150
+    }
+    END
+  }
+}
 
 builder_mixins {
   name: "android"
@@ -830,7 +841,11 @@ buckets {
     builders { mixins: "linux-try" name: "linux_chromium_msan_rel_ng" }
     builders { mixins: "linux-try" name: "linux_chromium_msan_variable" }
     builders { mixins: "linux-try" name: "linux_chromium_ozone_compile_only_ng" }
-    builders { mixins: "linux-try" name: "linux_chromium_rel_ng" }
+    builders {
+      mixins: "linux-try"
+      mixins: "goma-j150"
+      name: "linux_chromium_rel_ng"
+    }
     builders { mixins: "linux-try" name: "linux_chromium_tsan_rel_ng" }
     builders { mixins: "linux-try" name: "linux_chromium_tsan_variable" }
     builders { mixins: "linux-try" name: "linux_chromium_ubsan_rel_ng" }