Test cases for profiling

There's already a test case for the front page with 20 nodes, other obvious things to test:

Cached page as an anonymous user.
node/n (no comment form or comments)

node/n (comments and comment form, possibly with two different options for comments per page).

node/add/article

node_save()
comment_save()
user_save()
taxonomy_term_save()
- all of these both creating and updating.

menu_rebuild()

Theme registry rebuild.

Full cache clears, and the page following a full cache clear.

Some of these should be done with both the standard install profile and a 'bloated' install with all modules enabled.

A page callback that prints and exits (full bootstrap but no page rendering).

Most of these are pretty simple, I'll try to get some written.