infra: linux-goma-rbe-staging-rel uses -j150

Bug: 855319
Change-Id: I55e40c2162aff9ad2f127f4728cf8fea315d02e9
Reviewed-on: https://chromium-review.googlesource.com/c/1351324Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Commit-Queue: Simon Que <sque@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612138}

infra/config/global/cr-buildbucket.cfg

@@ -3043,7 +3043,11 @@ buckets {
     builders { mixins: "linux-try" name: "linux-blink-heap-incremental-marking" }
     builders { mixins: "linux-try" name: "linux-blink-heap-verification-try" }
     builders { mixins: "linux-try" name: "linux-dcheck-off-rel" }
-    builders { mixins: "linux-try" name: "linux-goma-rbe-staging-rel" }
+    builders {
+      mixins: "linux-try"
+      mixins: "goma-j150"
+      name: "linux-goma-rbe-staging-rel"
+    }
     builders { mixins: "linux-try" name: "linux-gcc-rel" }
     builders { mixins: "linux-try" name: "linux-jumbo-rel" }
     builders {