OSV-2022-621 Segv on unknown address in mpz_add

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49427 Crash type: Segv on unknown address Crash state: mpzadd mrbbintadd intadd...

OSV-2022-606 Heap-buffer-overflow in mrb_bint_add

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49282 Crash type: Heap-buffer-overflow READ 8 Crash state: mrbbintadd mrbintadd intadd...