RFR: 8275840: Add test to java/nio/channels/Channels/TransferTo.java to test transfer sizes > 2GB [v3]

[Markus KARG]

> Testing `FileChannel.transferTo(FileChannel)` with more than 2 GB of data is covering the case that *multiple* iterations of `FileChannel.transferTo(FileChannel)` are actually performed by the test.
> 
> This change was requested Alan Bateman @AlanBateman.

Markus KARG has updated the pull request incrementally with one additional commit since the last revision:

  Constants instead of local variables
  
  Signed-off-by: Markus Karg <markus at headcrashing.eu>

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6093/files
  - new: https://git.openjdk.java.net/jdk/pull/6093/files/04154625..126e4877

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6093&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6093&range=01-02

  Stats: 7 lines in 1 file changed: 4 ins; 2 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6093.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6093/head:pull/6093

PR: https://git.openjdk.java.net/jdk/pull/6093