visionOS: Update support for Xcode 15.2
Xcode 15.2 officially includes the visionOS SDKs. Update support:
- The target identification macros changed since the 15.0 beta.
- The deployment-target flag now uses
--taget=
instead of-mtargetos=
.
Also enable the visionOS test cases with Xcode 15.2.
Fixes: #25188 (closed)
Fixes: #25266 (closed)
Backport: release