Incompitabilities with some apps - looping lockscreen, freezes, etc.

[Maxr1998]

Description
There are multiple issues with the current lockscreen lifecycle which could trigger for some more or less special, but often widely used apps - regardless if using the Xposed app locker or the unreleased "no Xposed" option.

This can involve looping lockscreen ➰, crashing/freezing of the locked app 💀, the locked app being minimized after the first launch/unlock 🙈, the lockscreen appearing when navigating in-app 😳, the lockscreen not appearing at all 🏃‍♂️

Affected apps (some of them, from issues and own tests)

• AOSP Browser 💀
• Google Photos 🙈
• Hangouts 🙈 ➰
• WhatsApp 😳, also call screen locked even though it shouldn't
• Google Keep 💀
• Xposed Installer ➰
• ProtonMail 💀 (fix: unlock splash activity by default)
• Kik 🏃‍♂️
• Viber ➰
• Wire 🙈

[Maxr1998]

Instagram should be fixed now thanks to eb697c3.