NO-JIRA releaseBufferMemory just in case

This is just to make releaseBuffer to have the same semantic when no pool is used.

This has no effect on how the broker behaves as we always have it pooled.

artemis-journal/src/main/java/org/apache/activemq/artemis/core/io/nio/NIOSequentialFileFactory.java

@@ -134,7 +134,9 @@ public ByteBuffer allocateDirectBuffer(final int size) {
 
    @Override
    public void releaseDirectBuffer(ByteBuffer buffer) {
-      PlatformDependent.freeDirectBuffer(buffer);
+      if (buffer.isDirect()) {
+         PlatformDependent.freeDirectBuffer(buffer);
+      }
    }
 
    @Override
@@ -155,6 +157,8 @@ public ByteBuffer newBuffer(int size, boolean zeroed) {
    public void releaseBuffer(ByteBuffer buffer) {
       if (this.bufferPooling) {
          bytesPool.release(buffer);
+      } else {
+         releaseDirectBuffer(buffer);
       }
    }