Apple: Enable linking during iOS/tvOS/visionOS/watchOS toolchain inspection

Since commit 11da882a12 (Apple: Introduce separate system name for iOS,
tvOS, and watchOS, 2018-01-15, v3.14.0-rc1~14^2~1) our toolchain
inspection steps, like ABI detection, tell `try_compile` to use a
`STATIC_LIBRARY` instead of an `EXECUTABLE`.  This was needed at the
time to avoid codesign requirements.  However, commit d3a64c4e3f (Xcode:
Explicitly turn off signing in try_compile projects, 2020-07-16,
v3.19.0-rc1~483^2) introduced a more general solution to that problem.
Restore linking during toolchain inspection so that we can detect and
identify the linker.

Suggested-by: Marc Chevrier <marc.chevrier@gmail.com>
Fixes: #26443

Modules/Platform/iOS-Initialize.cmake

@@ -5,5 +5,3 @@ if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/(iPhoneOS|iPhoneSimulator|MacOSX)")
 endif()
 
 set(IOS 1)
-
-set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)

Modules/Platform/tvOS-Initialize.cmake

@@ -3,5 +3,3 @@ include(Platform/Darwin-Initialize)
 if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/AppleTV(OS|Simulator)")
   message(FATAL_ERROR "${CMAKE_OSX_SYSROOT} is not an tvOS SDK")
 endif()
-
-set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)

Modules/Platform/visionOS-Initialize.cmake

@@ -3,5 +3,3 @@ include(Platform/Darwin-Initialize)
 if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/XR(OS|Simulator)")
   message(FATAL_ERROR "${CMAKE_OSX_SYSROOT} is not an visionOS SDK")
 endif()
-
-set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)

Modules/Platform/watchOS-Initialize.cmake

@@ -3,5 +3,3 @@ include(Platform/Darwin-Initialize)
 if(NOT _CMAKE_OSX_SYSROOT_PATH MATCHES "/Watch(OS|Simulator)")
   message(FATAL_ERROR "${CMAKE_OSX_SYSROOT} is not an watchOS SDK")
 endif()
-
-set(_CMAKE_FEATURE_DETECTION_TARGET_TYPE STATIC_LIBRARY)