Compare test recording content deeply with Storable

The stored request content and the request testing content are
sometimes out of order when converted to strings, so we can also check
for deeply_equal with Storable::freeze.
Prereq a specific version of LWP::Protocol::PSGI

The latest version of LWP::Protocol::PSGI has a new guard feature that
leads to only one of the request/response pairs being
recorded. Downgrading to 0.04 instead of 0.06 restores the old
behavior where the entire test is recorded.