Fix fuzzing detected bug

src/core/ext/load_reporting/load_reporting.c

...pi_fuzzer_corpus/0e79b68aa8b9c336f0bbf9029928c53079711423

...pi_fuzzer_corpus/1560af88445d6c1e8b1300047f33056dce198e02

...pi_fuzzer_corpus/48caf755ddcc6c45d3416ba6ab44709f360eb82b

...pi_fuzzer_corpus/7030cb2c62b289459e459bc54bd84c8d7e6f5a98

...pi_fuzzer_corpus/81f8c545d77d93e6cb8239e9e4a4d7f8f8beeee9

...pi_fuzzer_corpus/b7d02f4d12cd0b5442a04675e69f98fbdabc775a

...pi_fuzzer_corpus/ce6a90cb7d395fea7aa54ee9f7061cc45f5494d7

...zer_corpus/crash-482e9bdce0e13df2a77eef75a1c07d38ee28f4ab

...pi_fuzzer_corpus/e94428d78182060ff6309dd626cf6b3ebeed88d6

tools/run_tests/tests.json