Change TaskIconMenu to lay out vertically

Still lays out horizontally when in phone
landscape.
TODO(b/186583656), need to center view.
Also have all layout be dynamic instead of having
some cases be in XML and some in code.

Bug: 181704764
Test: Task menu visible with all options in
portrait/landscape tablet
portrait phone
fake/real landscape phone

Change-Id: I3632eeb174f3e4baf2c9d69d51c1815c3c512e59