[Bug target/109501] vec_test_data_class defines missing

["chip.kerchner at ibm dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109501

--- Comment #5 from Chip Kerchner <chip.kerchner at ibm dot com> ---
Here's a testcase

```
#include <altivec.h>
#include <stdio.h>

int main()
{
  __vector float p4f = { float(0), float(1), float(2), float(3) };
  __vector __bool int nan_selector = vec_test_data_class(p4f,
__VEC_CLASS_FP_NAN);

  return 0;
}
```

```
NAN_defines.cpp: In function ‘int main()’:
NAN_defines.cpp:7:63: error: ‘__VEC_CLASS_FP_NAN’ was not declared in this
scope
    7 |   __vector __bool int nan_selector = vec_test_data_class(p4f,
__VEC_CLASS_FP_NAN);
      |                                                              
^~~~~~~~~~~~~~~~~~
```

```
/opt/gcc-nightly/trunk/bin/g++ -O3 -mcpu=power9 NAN_defines.cpp