[foreign-memaccess+abi] RFR: 8292037: Consider moving Linker::methodType as FunctionDescriptor::toMethodType [v2]

[Jorn Vernee]

> This patch moves `Linker::methodType` to `FunctionDescriptor` as `carrierMethodType`.
> 
> I went with the name `carrierMethodType` instead of `toMethodType` (as suggested by the JBS issue) since I think it's a bit more descriptive. Please let me know your thoughts.
> 
> This issue also suggest adding support for `SequenceLayout` in the linker implementation. I think adding support in FunctionDescriptor could be a good idea, but since passing arrays by value is not supported in C, I feel like we should reject it in the linker implementations we have (which are all C as well). Of course, we could make it work any way by interpreting such cases as a pointer layout instead, but it's a case of being able to do the same thing in multiple ways (which I think can be confusing), and might actually be surprising if someone passes the wrong layout to the linker by accident, but it doesn't get "caught".
> 
> I've added support for `SequenceLayout` to `FunctionDescriptor`, but it is still rejected in the type classification logic.

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

  add some simple tests

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Changes:
  - all: https://git.openjdk.org/panama-foreign/pull/717/files
  - new: https://git.openjdk.org/panama-foreign/pull/717/files/7698258e..807830ed

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=panama-foreign&pr=717&range=01
 - incr: https://webrevs.openjdk.org/?repo=panama-foreign&pr=717&range=00-01

  Stats: 22 lines in 1 file changed: 22 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/717.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign pull/717/head:pull/717

PR: https://git.openjdk.org/panama-foreign/pull/717