benchdnn: fix out-of-memory encountered on iGPU systems

Adds a new benchdnn_combined_limit for the combined device and CPU memory limit.
A new combined capacity factor was introduced, as the capacity factor appears
unnecessarily strict from what has been observed in practice. We likely could
increase the current capacity factor, but that is avoided in this patch to limit
the scope of this change.

Author: rjoursler

tests/benchdnn/dnnl_common.cpp

@@ -1129,6 +1129,7 @@ int check_total_size(res_t *res, dnnl_primitive_t prim_ref) {
     const double capacity_factor = 0.75;
     const double benchdnn_device_limit = capacity_factor * device_max_capacity;
     const double benchdnn_cpu_limit = capacity_factor * cpu_device_capacity;
+    const double benchdnn_combined_limit = 0.90 * cpu_device_capacity;
     assert(benchdnn_device_limit > 0 && benchdnn_cpu_limit > 0);
 
     auto dir_c_str = [&res]() {
@@ -1203,7 +1204,7 @@ int check_total_size(res_t *res, dnnl_primitive_t prim_ref) {
     size_t cpu_and_device_size
             = total_size_cpu + check_mem_size_args.total_size_device;
     bool fits_cpu_ram = cpu_and_device_size
-            <= (is_cpu() ? benchdnn_cpu_limit : cpu_device_capacity);
+            <= (is_cpu() ? benchdnn_cpu_limit : benchdnn_combined_limit);
 
     // Check combined size against CPU capacity as the simpler method to account
     // for integrated devices and mapping/unmapping memory.