Do not call disable / enable on null depot (#82542)

depot can be null if allocation_ring_buffer_size=0

Author: fmayer

compiler-rt/lib/scudo/standalone/combined.h

@@ -688,12 +688,14 @@ class Allocator {
     Quarantine.disable();
     Primary.disable();
     Secondary.disable();
-    Depot->disable();
+    if (Depot)
+      Depot->disable();
   }
 
   void enable() NO_THREAD_SAFETY_ANALYSIS {
     initThreadMaybe();
-    Depot->enable();
+    if (Depot)
+      Depot->enable();
     Secondary.enable();
     Primary.enable();
     Quarantine.enable();