launcher: use a different task menu for foldables

Foldables use a different menu from phones, positioned either to the
right or left of the app icon, and display an arrow. Since TaskMenuView
is very specific for handhelds, it was cleaner to create another class
to handle foldables case extending from ArrowPopup.

This creates a working menu, the correct style will come in later CLs.

Bug: 193432925
Test: open Overview and tap the app icon
Change-Id: Icb068954e1e20a52d80c16c52d8e38ce9a181a8b
Merged-In: Icb068954e1e20a52d80c16c52d8e38ce9a181a8b