ppc64le: StringKeyedTest.cpp: multilple errors: no matching function for call to 'std::_Hashtable<foo>' and so on

[mtasaka]

On ppc64le, Fedora 38, with gcc-12.1.1-4.fc38, 2022.08.15 folly/experimental/test/StringKeyedTest.cpp does not compile. Error log is large, so attaching. error2-ppc64le.log.txt