RFR(XS):JDK-8219228: java/util/Base64/TestEncodingDecodingLength.java failing on 8GB test machine.

Hello! I found that the test java/util/Base64/TestEncodingDecodingLength.java fails on a machine with 8GB memory after JDK-8218265. The test starts a VM with -Xmx8GB but the VM needs some more memory than only the heap and on machines with just 8GB of memory (and no swap configured) the test will always fail because the VM cannot get enough native memory. Therefore I suggest to increase "@requires os.maxMemory" to >= 10GB to be safe. Could someone please review this minimal change? Bug: https://bugs.openjdk.java.net/browse/JDK-8219228 Webrev: http://cr.openjdk.java.net/~azeller/webrevs/8219228/ Thanks and best regards, Arno