[foreign-memaccess+abi] RFR: 8317324: Add an overload to bind a memory segment var handle at an offset [v2]

[Maurizio Cimadamore]

> This PR adds an overload which binds a memory segment var handle offset coordinate to a provided constant value.
> 
> This is useful when the client knows that the accessed offset will be e.g. zero, or some other known constant value, thus reducing the number of coordinates that var handles clients will have to provide on each access.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Add overloads for other methods
  Fix javadoc

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Changes:
  - all: https://git.openjdk.org/panama-foreign/pull/900/files
  - new: https://git.openjdk.org/panama-foreign/pull/900/files/54c931c6..61eb2069

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=panama-foreign&pr=900&range=01
 - incr: https://webrevs.openjdk.org/?repo=panama-foreign&pr=900&range=00-01

  Stats: 124 lines in 6 files changed: 95 ins; 11 del; 18 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/900.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign.git pull/900/head:pull/900

PR: https://git.openjdk.org/panama-foreign/pull/900