mapi: Fixes non-constant-expression cannot be narrowed from type 'unsigned long' to 'unsigned int' in initializer list with clang

error is:
../src/mapi/glapi/tests/check_table.cpp:563:19: error: non-constant-expression cannot be narrowed from type 'unsigned long' to 'unsigned int' in initializer list [-Wc++11-narrowing]
   { "glNewList", _O(NewList) },

This is just a test and only with clang, and can be disabled by compiler option, so there is no need to back ported

Reviewed-by: Eric Engestrom <eric@igalia.com>
Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23793>

src/mapi/glapi/tests/check_table.cpp

@@ -28,7 +28,7 @@
 
 struct name_offset {
    const char *name;
-   unsigned int offset;
+   size_t offset;
 };
 
 extern const struct name_offset linux_gl_abi[];