Fix string output of `Base.format_bytes` when `binary=false` (#52932)
Introduced in [50572](https://github.com/JuliaLang/julia/pull/50572)
Before:
```
julia> Base.format_bytes(1, binary=false)
"1 "
julia> Base.format_bytes(11, binary=false)
"11 s"
```
This PR:
```
julia> Base.format_bytes(1, binary=false)
"1 byte"
julia> Base.format_bytes(11, binary=false)
"11 bytes"
```
Also add tests.