[foreign-memaccess+abi] RFR: 8299911: Refactor struct handling in AArch64 CallArranger [v2]

[Jorn Vernee]

> Refactor struct handling in AArch64 CallArranger.
> 
> Instead of having 6 very similar looking while loops, I've consolidated the storage allocation code for structs into a single helper method (`StorageCalculator::structStorages`). This should make it much easier to see which logic is being used for a particular case.

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

  clarify comment

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

Changes:
  - all: https://git.openjdk.org/panama-foreign/pull/765/files
  - new: https://git.openjdk.org/panama-foreign/pull/765/files/47dccef2..b9680432

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=panama-foreign&pr=765&range=01
 - incr: https://webrevs.openjdk.org/?repo=panama-foreign&pr=765&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/765.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign pull/765/head:pull/765

PR: https://git.openjdk.org/panama-foreign/pull/765