RFR: 8344912: Sharpen the return type of various internal methods in jdk.internal.foreign [v3]

[Quan Anh Mai]

> Hi,
> 
> This patch sharpens the return types of various internal methods. This helps the compiler to have better information when the corresponding methods are not inlined.
> 
> Please take a look and leave your reviews, thanks a lot.

Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:

  fix failing tests

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22344/files
  - new: https://git.openjdk.org/jdk/pull/22344/files/cf69f90f..d44b2ee5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22344&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22344&range=01-02

  Stats: 13 lines in 3 files changed: 7 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/22344.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22344/head:pull/22344

PR: https://git.openjdk.org/jdk/pull/22344