error: static assertion failed: Big endian requires a redesigned table

Another error on 10.6.8 Rosetta with `gcc12`:
```
/opt/local/var/macports/build/_opt_PPCRosettaPorts_devel_folly/folly/work/folly-v2022.08.01.00/folly/detail/base64_detail/Base64SWAR.cpp: In function 'uint32_t folly::detail::base64_detail::{anonymous}::base64DecodeSWARMainLoop(const char*&, const char*, char*&)':
/opt/local/var/macports/build/_opt_PPCRosettaPorts_devel_folly/folly/work/folly-v2022.08.01.00/folly/detail/base64_detail/Base64SWAR.cpp:101:14: error: static assertion failed: Big endian requires a redesigned table
101 | folly::kIsLittleEndian, "Big endian requires a redesigned table");
| ~~~~~~~^~~~~~~~~~~~~~~
```

Start with folly/detail/base64_detail/Base64SWAR.cpp at line 101 and reproduce the reported gcc12 build on 10.6.8 Rosetta. Trace the big-endian assertion and the surrounding decode table; done means the library builds successfully on the reported big-endian target without that assertion failure.

Written by the indexing model from the issue text.