Hi,

I made an embarrassing mistake in the fix for

  https://bugs.openjdk.java.net/browse/JDK-8151163
  All Buffer implementations should leverage Unsafe unaligned accessors

The offset calculation for Unsafe access was incorrect, it’s easy to get 
confused because for heap buffers the offset is relative to the array, and for 
direct buffers the address (which can update for slices/duplicates). 
Disturbingly all existing tests were passing both for core and hotspot when i 
pushed to hs.

As a penance i wrote a combinatorial test for buffer views to navigate the 
twisty maze of heap/direct, aligned/unaligned, little/big endian for accessing 
binary data and views from the source buffer.

Please review:

  
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8162458-byte-buffer-view-offset-access-incorrect/webrev/

(This may be a duplicate of [1]).

Test has been verified to fail with the existing code. Focused JPRT runs pass, 
but i will kick off core/hotspot runs later on today.

I will push to hs since that is where JDK-8151163 and it has not been 
integrated into jdk9/dev.

Paul.

[1] https://bugs.openjdk.java.net/browse/JDK-8159257
unsafe.cpp: assert(byte_offset < p_size) failed: Unsafe access: offset 32767 > 
object's size 16

For the test runtime/Unsafe/RangeCheck.java I can reproduce a crash in jdk9/dev 
which does not have JDK-8151163, and i can reproduce on jdk9/hs with this fix 
for JDK-8162458.

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