DevTools: [Console] use filtering to collapse and expand console groups

Collapsing/expanding groups in console is just a special case of console
message filtering.

This patch unifies codepaths for both filtering and
group collapsing, simplifies ConsoleGroup and
introduces additional ConsoleGroupViewMessage which tracks if the group
is collapsed.

Review URL: https://codereview.chromium.org/254833004

git-svn-id: svn://svn.chromium.org/blink/trunk@172739 bbb929c8-8fbe-4397-9dbb-9b2b20218538