KVM: selftests: Always unlink memory regions when deleting (VM free)

Unlink memory regions when freeing a VM, even though it's not strictly
necessary since all tracking structures are freed soon after.  The time
spent deleting entries is negligible, and not unlinking entries is
confusing, e.g. it's easy to overlook that the tree structures are
freed by the caller.

Link: https://lore.kernel.org/r/20240802201429.338412-1-seanjc@google.comSigned-off-by: Sean Christopherson <seanjc@google.com>

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -712,16 +712,13 @@ void kvm_vm_release(struct kvm_vm *vmp)
 }
 
 static void __vm_mem_region_delete(struct kvm_vm *vm,
-				   struct userspace_mem_region *region,
-				   bool unlink)
+				   struct userspace_mem_region *region)
 {
 	int ret;
 
-	if (unlink) {
-		rb_erase(&region->gpa_node, &vm->regions.gpa_tree);
-		rb_erase(&region->hva_node, &vm->regions.hva_tree);
-		hash_del(&region->slot_node);
-	}
+	rb_erase(&region->gpa_node, &vm->regions.gpa_tree);
+	rb_erase(&region->hva_node, &vm->regions.hva_tree);
+	hash_del(&region->slot_node);
 
 	region->region.memory_size = 0;
 	vm_ioctl(vm, KVM_SET_USER_MEMORY_REGION2, &region->region);
@@ -762,7 +759,7 @@ void kvm_vm_free(struct kvm_vm *vmp)
 
 	/* Free userspace_mem_regions. */
 	hash_for_each_safe(vmp->regions.slot_hash, ctr, node, region, slot_node)
-		__vm_mem_region_delete(vmp, region, false);
+		__vm_mem_region_delete(vmp, region);
 
 	/* Free sparsebit arrays. */
 	sparsebit_free(&vmp->vpages_valid);
@@ -1200,7 +1197,7 @@ void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa)
  */
 void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot)
 {
-	__vm_mem_region_delete(vm, memslot2region(vm, slot), true);
+	__vm_mem_region_delete(vm, memslot2region(vm, slot));
 }
 
 void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t base, uint64_t size,