[foreign-memaccess+abi] RFR: 8305170: Add MemoryLayout::withoutAlignment as an alias for withAlignment(8)

[Per Minborg]

This PR proposes to add new methods to the many MemoryLayout classes called `withoutAlignment()` and that is an alias of calling `withAlignment(1)`.

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Commit messages:
 - Use new method
 - Add MemoryLayout::withoutAlignment

Changes: https://git.openjdk.org/panama-foreign/pull/852/files
 Webrev: https://webrevs.openjdk.org/?repo=panama-foreign&pr=852&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305170
  Stats: 145 lines in 12 files changed: 130 ins; 0 del; 15 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/852.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign.git pull/852/head:pull/852

PR: https://git.openjdk.org/panama-foreign/pull/852