The names naming_amd64.go and naming_amd64_test.go carried the _amd64
filename suffix, which the go tool reads as an implicit GOARCH=amd64
build constraint: the tables disappeared from every non-amd64 build
and the package failed to compile for arm64, riscv64 and loong64, the
other three architectures the tool assembles. Renaming to
amd64_naming.go removes the constraint; the module builds again for
all four GOARCH values.
Assisted-by: GLM 5.3
