RFR: 8272654: Mark word accesses should not use Access API

[Aleksey Shipilev]

See the bug for discussion.

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Commit messages:
 - Initial change

Changes: https://git.openjdk.java.net/jdk/pull/5166/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5166&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272654
  Stats: 8 lines in 1 file changed: 0 ins; 3 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5166.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5166/head:pull/5166

PR: https://git.openjdk.java.net/jdk/pull/5166