Use orientationIndex enum from header

[cwoffenden]

As suggested in #21428 the enum value was taken from the header.

In the process, since adding to struct_info.json was needed, a fix to the reported path prompting to run gen_struct_info.py was added.

[cwoffenden]

Failures seem to be down to changes in generated_struct_info64.json not matching the older version.

[cwoffenden]

Note to a future me, because this will trip me up again in six months...

 emcc --clear-cache
 ./tools/maint/gen_struct_info.py
 ./tools/maint/gen_struct_info.py --wasm64
 ./tools/maint/gen_sig_info.py