OSV-2026-582 Use-of-uninitialized-value in H5S_select_hyperslab

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=502905691 Crash type: Use-of-uninitialized-value Crash state: H5Sselecthyperslab H5Dchunkioinit H5Dread...