[foreign-jextract] RFR: 8277645: TreeMaker should not call type() on pointer types too early [v2]

[Maurizio Cimadamore]

> This patch fixes a couple of callsites in TreeMaker which were calling `DelegatedType::type`.
> 
> `DelegatedType` is a common supertype for both typedef types and pointer types. The reason why `TreeMaker` calls that method is to recover the *canonical* type of a typedef.
> 
> Unfortunately, as `TreeMaker` doesn't check the delegated type kind, it can sometime call `type()` on a delegated type whose kind is `POINTER`. The way in which the jextract parser is setup is such that pointee types can only be accessed *after* parsing has completed.
> 
> This issue only occurs under very rare circumstances, that is when a type qualifier (other than the usual ones, such as `const`) is used on a pointer typedef - such as `__ptr64`. In such cases, the clang AST sees an `AttributedType` and not a `QualifiedType`, which throws our parsing logic off-guard.
> 
> The solution is to check for the delegated type kind before attempting to call `type()`, and only call it when its kind is `TYPEDEF`. To test this I used the special clang flag `-fms-extensions` which allows to use the MS extensions even on Linux/Mac.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Fix bogus references to other test

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/616/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/616/files/6ec7b28d..24f0fe43

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=616&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=616&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/616.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/616/head:pull/616

PR: https://git.openjdk.java.net/panama-foreign/pull/616