Revert "Allow bypass on ARM with MUTTER_ALLOW_BYPASS_COMPOSITOR envvar"

This reverts commit 1431778953dde3ef63d8491fffe1de0d1edcc206.
We have a fixed Mali binary where this is no longer necessary.

[endlessm/eos-shell#3775]
Merge pull request #24 from endlessm/shell/3775

Revert "Allow bypass on ARM with MUTTER_ALLOW_BYPASS_COMPOSITOR envvar"
Merge branch 'master' for Release_2.1.9-rc6