Stop using File::Slurp
Stop using File::Slurp

it's not a core module, and more importantly, the error
message sucks when it's missing (because the TAP harness
swallows it up by default).

cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp