RFR: 8283022: com/sun/crypto/provider/Cipher/AEAD/GCMBufferTest.java failing with -Xcomp after 8273297

[Smita Kamath]

When input length provided to the intrinsic is 8192, only 7680 bytes are processed as the intrinsic operates on multiples of 768 bytes.
In implGCMCrypt(ByteBuffer src, ByteBuffer dst) method, 
dst.put(bout, 0, PARALLEL_LEN) statement caused the ciphertext mismatch as PARALLEL_LEN was set to 8192. 
Since the intrinsic only processed 7680 bytes, the rest output was incorrect.

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Commit messages:
 - Changed PARALLEL_LEN to 7680 as intrinsic processes multiples of 768 bytes

Changes: https://git.openjdk.java.net/jdk/pull/8280/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8280&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283022
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8280.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8280/head:pull/8280

PR: https://git.openjdk.java.net/jdk/pull/8280