[foreign-memaccess] RFR: Memory access implementation rewrite - post cleanup

[Maurizio Cimadamore]

* Fix access modes not preserved in AbstractMemorySegmentImpl.ofBuffer
* Add check to ensure that Foreign::withSize and Foreign::asMallocSegment are called with unchecked address

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

Commit messages:
 - * Fix access modes not preserved in AbstractMemorySegmentImpl.ofBuffer
 - Update src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/HeapMemorySegmentImpl.java
 - Update src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/AbstractMemorySegmentImpl.java
 - Update src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/NativeMemorySegmentImpl.java
 - Fix typo in javadoc
 - Remove redundant @ForceInline annos
 - Fix silly mistake in MappedMemorySegment factory
 - Revert changes to LoopOverNonConstant
 - Add benchmark for on-heap segments
 - Fixed issue with HeapSegment::dup
 - Add logic to enable/disable small segment support from command line
 - Fix mapped byte buffer integration
 - Fix performances for on-heap segments; this requires splitting out the various heap segment classes,
 - * Minor tweak to HeapSegment impl
 - Rearrange memory segment implementation hierarchy
 - Tweaked code
 - Fixup code
 - Rewrite - better performances
 - Update impl - performance still horrible in the acquire() case
 - Implementation rough rewrite - passes all tests

Changes: https://git.openjdk.java.net/panama-foreign/pull/110/files
 Webrev: https://webrevs.openjdk.java.net/panama-foreign/110/webrev.00
  Stats: 1858 lines in 24 files changed: 1283 ins; 521 del; 54 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/110.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/110/head:pull/110

PR: https://git.openjdk.java.net/panama-foreign/pull/110