RFR: 8319316: Clarify text around which layouts a linker supports [v3]

[Jorn Vernee]

> - Add linker note about packed structs.
> - Relax language a bit to avoid implying that only listed layouts are supported.

Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:

  Add 'strict'
  
  Co-authored-by: Maurizio Cimadamore <54672762+mcimadamore at users.noreply.github.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/16485/files
  - new: https://git.openjdk.org/jdk/pull/16485/files/fea8a263..b9770e0e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16485&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16485&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16485.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16485/head:pull/16485

PR: https://git.openjdk.org/jdk/pull/16485