Mark IL_VERSION as optional query (#21661)

NativeCPU executes native code directly without intermediate language
(IL) support, so UR_DEVICE_INFO_IL_VERSION query is not applicable.

Changes:
1. Mark IL_VERSION as [optional-query] in device.yml spec
2. Add explanatory comment to ur_api.h describing why this is optional
3. Add IL_VERSION to optional_queries.h list
4. Remove xfails for NativeCPU from SuccessILVersion test
5. Add comment to test explaining why query is optional

The test now correctly handles UNSUPPORTED_ENUMERATION as a valid
response for adapters without IL support.

Author: kekaczma

include/unified-runtime/ur_api.h

@@ -2204,7 +2204,8 @@ typedef enum ur_device_info_t {
   /// It is unsuitable for general use in applications. This feature is
   /// provided for identifying memory leaks.
   UR_DEVICE_INFO_REFERENCE_COUNT = 64,
-  /// [char[]] null-terminated IL version
+  /// [char[]][optional-query] null-terminated IL version. Optional as not
+  /// all adapters support IL (e.g., NativeCPU).
   UR_DEVICE_INFO_IL_VERSION = 65,
   /// [char[]] null-terminated device name
   UR_DEVICE_INFO_NAME = 66,

scripts/core/device.yml

@@ -333,7 +333,7 @@ etors:
             The reference count returned should be considered immediately stale.
             It is unsuitable for general use in applications. This feature is provided for identifying memory leaks.
     - name: IL_VERSION
-      desc: "[char[]] null-terminated IL version"
+      desc: "[char[]][optional-query] null-terminated IL version. Optional as not all adapters support IL (e.g., NativeCPU)."
     - name: NAME
       desc: "[char[]] null-terminated device name"
     - name: VENDOR

test/conformance/device/urDeviceGetInfo.cpp

@@ -1145,9 +1145,9 @@ TEST_P(urDeviceGetInfoTest, SuccessReferenceCount) {
                              property_value);
 }
 
+// Optional query: Not all adapters support intermediate language (IL).
+// NativeCPU executes native code directly without IL support.
 TEST_P(urDeviceGetInfoTest, SuccessILVersion) {
-  UUR_KNOWN_FAILURE_ON(uur::NativeCPU{});
-
   size_t property_size = 0;
   const ur_device_info_t property_name = UR_DEVICE_INFO_IL_VERSION;