The commandLine.hasSwitch and commandLine.getSwitchValue tests append
switches (foobar1, foobar) that are never removed. These persist for
the entire process lifetime, which could affect tests that check for
switch presence or absence if test ordering changes.

Add afterEach hooks that call removeSwitch for each appended switch.

Co-authored-by: Charles Kerr <charles@charleskerr.com>

The 'validates process APIs access in sandboxed renderer' test sets
process.env.sandboxmain = 'foo' without cleaning it up. This env var
persists for all subsequent tests and could affect tests that compare
process.env snapshots.

Use defer() to delete the env var after the test completes.

Co-authored-by: Charles Kerr <charles@charleskerr.com>

The release-notes spec sets NOTES_CACHE_PATH in before() but never
deletes it. This env var persists for all subsequent test files and
could interfere with any code that checks for its presence.

Add an after() hook to delete the env var when the suite completes.

Co-authored-by: Charles Kerr <charles@charleskerr.com>

The app name tests restore app.name at the end of each test body. If
an assertion fails before the restoration line, the name stays
corrupted for all subsequent tests.

Move restoration to an afterEach hook so it always runs, and remove
the now-redundant inline restoration calls.

Co-authored-by: Charles Kerr <charles@charleskerr.com>

The 'can download from custom protocols' test registers an HTTP
protocol handler on session.defaultSession but never unregisters it.
This handler persists globally and could interfere with other tests
that use the same protocol name or the default session.

Use defer() to ensure the protocol is unregistered after the test.

Co-authored-by: Charles Kerr <charles@charleskerr.com>

The 'reporting api' test sets setCertificateVerifyProc on
defaultSession to accept all certificates, but the finally block
only destroys the window and closes the server. The permissive
certificate handler persists globally, causing all subsequent tests
using defaultSession HTTPS requests to skip certificate verification.

Reset the handler to null in the finally block.

Co-authored-by: Charles Kerr <charles@charleskerr.com>