Decrease forks on the bots

This could be causing the latest timeouts if we go into gc madness

This could also be causing the OOM that happened on the release bot

Bug: 203392723

Change-Id: I0d871ee40982d2d940bdec50e74224f00b25c8c2
diff --git a/build.gradle b/build.gradle
index 3c96101..8b08d17 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1717,7 +1717,7 @@
       maxParallelForks = processors.intdiv(3) ?: 1
       // On low cpu count machines (bots) we under subscribe, so increase the count.
       if (processors == 8) {
-        maxParallelForks = 4
+        maxParallelForks = 3
       }
     }
     println("NOTE: Max parallel forks " + maxParallelForks)