bottle: fix regex

tests: clean up file system for all tests

Noted that this is intended for the revision of this formula instead of
rebuild of a bottle.

These locations are now all automatically cleaned up after every test.

These are no longer necessary.

(No longer just integration tests.)

tests: reset ARGV in teardown

tests: clear tab cache in global teardown

tests: enforce `super` in lifecycle hooks

This will allow us to have global setup and teardown for tests.

For example, we can automatically clear caches after each test, to avoid
annoying intermittent failures like #1879 and #1886.

Simplify Keg class

This seems to be a remnant of Ruby 1.8.

tests: add a missing Tab cache clear

Similar to 6fc1747e. I hadn't seen any
test failures caused by this, but I noticed it in the process of
trackign that down and it's an accident waiting to happen.

This was responsible for the sporadic failures I encountered in #1878.

tab: store installed_as_dependency, installed_on_request.

Also, report formulae installed on request. This is useful in
differentiating between those formulae that are popular because they
are widely requested and those that are popular because they are widely
depended on.

Which, in turn, provides them for `brew info --json=v1` so other tools
such as e.g. `brew bundle` can make use of this information.

These are used to determine whether or not a formula’s install was
specifically requested by a user and/or pulled in as a dependency.

integration_command_test_case: improve fail output

Instead of `puts`ing when the failure occurs save it until the error
message and print a prose description of what the failure was and the
output from the command. This makes the output from failing tests
significantly easier to read.

bottle: add: improve regexp to recognize comments

audit: only warn on versioned conflicts_with.

uses: properly handle untapped formulae in recursive dependency expansion (again!)

uses: fix recursive requirement resolution

Rather than all versioned formulae regardless. Oops.

This would have eliminated the need for Homebrew/homebrew-core#9000, for
instance.

Add `keg_only :versioned_formula`.

suite_test: skip flaky test.