[CMake][AIX] Enable CMP0182: Create shared library archives by default (#155686)

On AIX we prefer to create shared libraries as shared library archives
(i.e. we archive the shared object in a big AR archive) as this is the
standard format on the platform.

There is now a CMake policy that allows us to do this by default, so
opt-in to that behaviour.

---------

Co-authored-by: Hubert Tong <[email protected]>

Author: daltenty

cmake/Modules/CMakePolicy.cmake

@@ -41,3 +41,9 @@ if(POLICY CMP0156)
     cmake_policy(SET CMP0179 NEW)
   endif()
 endif()
+
+# CMP0182: Create shared library archives by default on AIX.
+# New in CMake 4.0: https://cmake.org/cmake/help/latest/policy/CMP0182.html
+if(POLICY CMP0182)
+  cmake_policy(SET CMP0182 NEW)
+endif()