[UR] Stop using extension strings to report support for exp features.

With this change all experimental features now add a ur_device_info_t
enum which adapters report support through, and all EXTENSION_STRING
macros have been removed.

Author: aarongreig

sycl/cmake/modules/FetchUnifiedRuntime.cmake

@@ -116,7 +116,7 @@ if(SYCL_UR_USE_FETCH_CONTENT)
       CACHE PATH "Path to external '${name}' adapter source dir" FORCE)
   endfunction()
 
-  set(UNIFIED_RUNTIME_REPO "https://github.com/oneapi-src/unified-runtime.git")
+  set(UNIFIED_RUNTIME_REPO "https://github.com/aarongreig/unified-runtime.git")
   include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules/UnifiedRuntimeTag.cmake)
 
   set(UMF_BUILD_EXAMPLES OFF CACHE INTERNAL "EXAMPLES")

sycl/cmake/modules/UnifiedRuntimeTag.cmake

@@ -1,7 +1 @@
-# commit 2eae687a4cf24ba02ee8e9ebb9552c1d392972ee
-# Merge: 1ba7f39a 2a081891
-# Author: Callum Fare <[email protected]>
-# Date:   Mon Nov 11 13:35:24 2024 +0000
-#     Merge pull request #2112 from martygrant/martin/context-cts-spec-gap
-#     Improvements to align CTS and Spec for Context
-set(UNIFIED_RUNTIME_TAG 2eae687a4cf24ba02ee8e9ebb9552c1d392972ee)
+set(UNIFIED_RUNTIME_TAG aaron/stopUsingURExtStrings)