RFR: 8268388: Update large pages information in Java manpage

[Stefan Johansson]

Please review this update to the text for large pages in the Java man page. 

The text for `LargePageSizeInBytes` was reviewed in this [CSR](https://bugs.openjdk.java.net/browse/JDK-8265517), and this change will integrate them into the actual man page. The *Large Pages* section further down in the man page was also a bit out-dated and have been brushed up a bit.

-------------

Commit messages:
 - Thomas review.
 - 8268388: Update large pages information in Java manpage

Changes: https://git.openjdk.java.net/jdk/pull/4425/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4425&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268388
  Stats: 73 lines in 1 file changed: 18 ins; 8 del; 47 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4425.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4425/head:pull/4425

PR: https://git.openjdk.java.net/jdk/pull/4425