RFR: JDK-8304828: Lots of constant static data not declared static const in cpu/x86

[Justin King]

Simple refactor that updates declarations and definitions for data that is effectively static and constant to be `static` and/or `const`. Helps make sure we do not break the one definition rule and helps the compiler/linker to place the data in read-only sections of the executable.

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Commit messages:
 - Make static const data static const

Changes: https://git.openjdk.org/jdk/pull/13163/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13163&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304828
  Stats: 166 lines in 27 files changed: 0 ins; 0 del; 166 mod
  Patch: https://git.openjdk.org/jdk/pull/13163.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13163/head:pull/13163

PR: https://git.openjdk.org/jdk/pull/13163