hdf5: fix []C.hid_t <-> []uint type prunning

there are many places where we do:

```go
func f(vs []uint) {
cvs := (*C.hid_t)(unsafe.Pointer(&vs[0]))
C.cfunc(C.int(len(vs)), cvs)
}
```

(or equivalent.)

either replace all these type prunning snippets or insert a `func init()` that checks this type prunning is actually working for the platform/OS/compiler setup at hand.

Search the repository for []uint-to-C.hid_t conversions and equivalent cgo calls. Check how these conversions behave across the relevant platform, OS, and compiler setups, then determine whether all call sites need replacement or whether startup validation is sufficient; done means every affected conversion is covered.

Written by the indexing model from the issue text.