add valgrind instrumentation

currently, our valgrind instrumentation is empty:

#define VALGRIND_DO_MEMPOOL_ALLOC(pool, ptr, size)                             \
    do {                                                                       \
        (void)(pool);                                                          \
        (void)(ptr);                                                           \
        (void)(size);                                                          \
    } while (0)

#define VALGRIND_DO_MEMPOOL_FREE(pool, ptr)                                    \
    do {                                                                       \
        (void)(pool);                                                          \
        (void)(ptr);                                                           \
    } while (0)
#endif

additionally, our GPU workflows should be run with all instrumentation enabled (could be done in Nightly builds)

Locate the VALGRIND_DO_MEMPOOL_ALLOC and VALGRIND_DO_MEMPOOL_FREE macro definitions and identify the GPU workflow configuration. Start by checking how instrumentation is currently disabled, then verify that the macros perform the intended Valgrind mempool operations and that GPU workflows run with instrumentation enabled.