RFR: 8254360: Re-examine use of CodeBuffer::verify_section_allocation [v2]

[Claes Redestad]

> - In release builds, only call `verify_section_allocation` in `~CodeBuffer`. This reduce overhead, while retaining most of the verification promises in product builds.
> - Minor touch-ups the implementation of `verify_section_allocation`: Use is_aligned. Add a `disjoint` predicate. Only compare two sections once per verification. Remove some redundant checks.

Claes Redestad has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - Fix copyright
 - Fix indentation, copyright
 - Merge branch 'master' into verify_section_alloc
 - Merge branch 'master' into verify_section_alloc
 - Merge branch 'master' into verify_section_alloc
 - Ptrs schmtrs
 - Factor out disjoint property, avoid redundant checks (disjointedness is symmetric)
 - 8254360: Re-examine use of CodeBuffer::verify_section_allocation

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1421/files
  - new: https://git.openjdk.java.net/jdk/pull/1421/files/91665791..7a972eb2

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1421&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1421&range=00-01

  Stats: 2189 lines in 72 files changed: 1478 ins; 339 del; 372 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1421.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1421/head:pull/1421

PR: https://git.openjdk.java.net/jdk/pull/1421