Assertion failure from H5VL_NATIVE macro

**Describe the bug**

The following simple code causes an assertion failure in debug builds of HDF5 due to
entering the library in a way that doesn't initialize it. As the initialization function that
this macro maps to is a public function, it should likely be converted from a
FUNC_ENTER_NOAPI function to a FUNC_ENTER_API function.

```C
#include "hdf5.h"

int
main(int argc, char **argv)
{
H5VL_NATIVE;
return 0;
}
```

**Expected behavior**

No assertion failure should be encountered.

**Platform**
- HDF5 version **develop (32ee132b0bc8fcd5ecc2306d2a3900f34c956d32)**
- OS and version **N/A**
- Compiler and version **N/A**
- Build system (e.g. CMake, Autotools) and version **N/A**
- Any configure options you specified **Debug build**