[java] use the correct base64 decoder (#11107)

use the correct decoder

The slightly wrong decoder was used to decode base64, using this decoder
will copy the byte array at the end of decoding. Using the correct one,
based on the W3C WebDriver specification, will not copy the byte array
after decoding it.

Author: joerg1985

java/src/org/openqa/selenium/OutputType.java

@@ -55,7 +55,7 @@ public String toString() {
   OutputType<byte[]> BYTES = new OutputType<byte[]>() {
     @Override
     public byte[] convertFromBase64Png(String base64Png) {
-      return Base64.getMimeDecoder().decode(base64Png);
+      return Base64.getDecoder().decode(base64Png);
     }
 
     @Override