This removes a level of indentation from all commands without
introducing any dummy functions.

Fixes copy-paste issue in `test_pep518_forkbombs`.

Rename stub package required_by_mixed_cap to requires_requires_cap
Move the canonicalize_name calculation outside of a loop

in pip show
Remove useless import in stubs for named tests

Add test to check if a capitalized name is being shown properly
Add new stub package to support the test

It fails if it already satisfies the requirement, when
pip has been modifying via `pip.exe install ...` command.

Fix typos
Use script.pip instead of script.run

Rebased to the latest master
Remove unneeded assertions
Use create_basic_wheel_for_package
Couple other nitpicks

Fix typos and remove unneeded assertions.

Handle the case of invoking pip via pip3 and pip3.7

Closes #1373.

This resulted in an approximate 24% speed-up of a vanilla `pip`
invocation on one system (0.477 secs before, 0.363 secs after).

It didn't seem related with the rest of the locations module