RFR: 8292446: Make TableRateStatistics optional in CHT [v2]

[Johan Sjölén]

> Right now the footprint of disabling statistics for tables where they're not used is minimal as they're single instance and static. We're working on using CHT in more contexts, where it will be dynamically allocated, and then these changes will add up to something more substantial.

Johan Sjölén has updated the pull request incrementally with two additional commits since the last revision:

 - Uninitialized pointers do not default to nullptr
 - Fixes

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9899/files
  - new: https://git.openjdk.org/jdk/pull/9899/files/012e001a..79ea2602

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9899&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9899&range=00-01

  Stats: 4 lines in 2 files changed: 1 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/9899.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9899/head:pull/9899

PR: https://git.openjdk.org/jdk/pull/9899