memset for api fuzzer

test/core/end2end/fuzzers/api_fuzzer.c

@@ -697,6 +697,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
           break;
         }
         grpc_op *ops = gpr_malloc(sizeof(grpc_op) * num_ops);
+        memset(ops, 0, sizeof(grpc_op) * num_ops);
         bool ok = true;
         size_t i;
         grpc_op *op;