It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

This reverts commit cc1cf13e.

This reverts commit e22f9974.

Adding the exit(exitCode) fixes the hang.
Tested by running `fx run-host-tests` with a topaz checkout.
Verified the hang before, no hang after.

This reverts commit 032f8cdb.

The test runner hangs on exit after all tests pass when trying
to roll this into Fuchsia.

This allows us to collect code coverage for Fuchsia tests.

This updates AppContext per the recommendations in #15352

Fixes #15352

* Populate AnsiTerminal in context for daemon launches

* Strip out AnsiTerminal additions to context since they are no longer needed

Previously, the usage analytics would generate a write to the user's
HOME directory during the Fuchsia build. We're tightening down the
environment in which we run the Fuchsia build, and these writes are now
more obvious.

This patch removes the usage analytics during the Fuchsia build,
avoiding the write to the user's HOME directory.

* round 3

* partially address comments

* merge

* review notes

* review

* review

* review

Currently this just prints the observatory URL as a JSON event.
Refactored the code to make this fit in.