Only output dynamic scheduling debug logs when --debug_spawn_scheduler is on.

PiperOrigin-RevId: 405343425
diff --git a/src/main/java/com/google/devtools/build/lib/dynamic/DynamicSpawnStrategy.java b/src/main/java/com/google/devtools/build/lib/dynamic/DynamicSpawnStrategy.java
index 5ab2862..fb91c57 100644
--- a/src/main/java/com/google/devtools/build/lib/dynamic/DynamicSpawnStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/dynamic/DynamicSpawnStrategy.java
@@ -506,7 +506,9 @@
 
   @FormatMethod
   private void debugLog(String fmt, Object... args) {
-    stepLog(Level.FINE, null, fmt, args);
+    if (options.debugSpawnScheduler) {
+      stepLog(Level.FINE, null, fmt, args);
+    }
   }
 
   @Override