test: drop whitespace after shell redirection operators

test: drop whitespace after shell redirection operators

(The one case that is left unchanged is '< <(subcommand)'.)

This way, the style with no gap was already dominant. This way, the reader
immediately knows that ' < ' is a comparison operator and ' << ' is a shift.

In a few cases, replace custom EOF replacement by just EOF. There is no point
in using someting like "_EOL" unless "EOF" appears in the text.