Fix percent decode fuzzer

test/core/slice/percent_decode_fuzzer.cc

@@ -31,9 +31,8 @@ bool squelch = true;
 bool leak_check = true;
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  struct grpc_memory_counters counters;
+  grpc_core::testing::LeakDetector leak_detector(true);
   grpc_init();
-  grpc_memory_counters_init();
   grpc_slice input = grpc_slice_from_copied_buffer((const char*)data, size);
   grpc_slice output;
   if (grpc_strict_percent_decode_slice(
@@ -46,9 +45,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   }
   grpc_slice_unref(grpc_permissive_percent_decode_slice(input));
   grpc_slice_unref(input);
-  counters = grpc_memory_counters_snapshot();
-  grpc_memory_counters_destroy();
   grpc_shutdown();
-  GPR_ASSERT(counters.total_size_relative == 0);
   return 0;
 }