OSV-2023-200 Segv on unknown address in mrb_vm_find_method

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=57135 Crash type: Segv on unknown address Crash state: mrbvmfindmethod mrbvmexec mrbvmrun...

OSV-2023-151 UNKNOWN READ in mrb_vm_find_method

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=56687 Crash type: UNKNOWN READ Crash state: mrbvmfindmethod mrbvmexec mrbvmrun...