Small performance improvement.

h2/src/main/org/h2/store/Data.java

@@ -1014,14 +1014,19 @@ public class Data {
      */
     public void checkCapacity(int plus) {
         if (pos + plus >= data.length) {
-            byte[] d = Utils.newBytes((data.length + plus) * 2);
-            // must copy everything, because pos could be 0 and data may be
-            // still required
-            System.arraycopy(data, 0, d, 0, data.length);
-            data = d;
+            // a separate method to simplify inlining
+            expand(plus);
         }
     }
 
+    private void expand(int plus) {
+        byte[] d = Utils.newBytes((data.length + plus) * 2);
+        // must copy everything, because pos could be 0 and data may be
+        // still required
+        System.arraycopy(data, 0, d, 0, data.length);
+        data = d;
+    }
+
     /**
      * Fill up the buffer with empty space and an (initially empty) checksum
      * until the size is a multiple of Constants.FILE_BLOCK_SIZE.