The allocator code has already changed a fair amount since that PR landed, so
only docstrings needed to be rewritten.

This covers these commits:
9dbdfe9
e6803d7

…) signature"

The signature fix itself is trivial, just adding a `&`. The test changes had
already been partially rewritten during the freestanding table function
refactor. Now alter constants and variable names, remove a use of `as`, and free
the memory at the end.

The PR originally included a cleanup commit ("uefi-test-runner: Fix buffer
alignment on ia32") that ended up being cherry-picked and merged in a separate
PR: rust-osdev#844. Rewrite that fix here as
well.

This covers these commits:
d7697c3
9609873

This covers these commits:
d4e88a1