Improve java/io/BufferedInputStream/LargeCopyWithMark.java using jtreg tags

The test java/io/BufferedInputStream/LargeCopyWithMark.java uses a system property and a child process to do things which can now be done with jtreg tags. Specifically, the use of the “os.arch” property to check for a 64-bit platform can be replaced with “@requires”, and passing “-Xmx4G” can be done via the “@run” tag instead of using a child process.