Change Remote Cache default size

With the new snmalloc2 changes it seems the larger window is leading to
more fragmentation and harming performance.  Reducing size still
provides good batching, improves memory overhead.

Author: mjp41

src/mem/allocconfig.h

@@ -16,14 +16,6 @@ namespace snmalloc
 #endif
     ;
 
-  // Return remote small allocs when the local cache reaches this size.
-  static constexpr int64_t REMOTE_CACHE =
-#ifdef USE_REMOTE_CACHE
-    USE_REMOTE_CACHE
-#else
-    1 << 20
-#endif
-    ;
   enum DecommitStrategy
   {
     /**
@@ -91,4 +83,13 @@ namespace snmalloc
   static_assert(
     MIN_ALLOC_SIZE >= (sizeof(void*) * 2),
     "MIN_ALLOC_SIZE must be sufficient for two pointers");
+
+  // Return remote small allocs when the local cache reaches this size.
+  static constexpr int64_t REMOTE_CACHE =
+#ifdef USE_REMOTE_CACHE
+    USE_REMOTE_CACHE
+#else
+    1 << MIN_CHUNK_BITS
+#endif
+    ;
 } // namespace snmalloc