RFR: JDK-8301171: Rename sanitizers/address.h to sanitizers/address.hpp

[Justin King]

Trivial change updating header to use `.hpp` instead of `.h`. I accidentally used `.h` out of habit even though Hotspot consistently uses `.hpp`.

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

Commit messages:
 - Rename sanitizers/address.h to sanitizers/address.hpp

Changes: https://git.openjdk.org/jdk/pull/12224/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12224&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301171
  Stats: 3 lines in 4 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/12224.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12224/head:pull/12224

PR: https://git.openjdk.org/jdk/pull/12224