DevTools: speculative fix of inspector/console/console-viewport-selection.html

This patch speculatively fixes flakiness of
inspector/console/console-viewport-selection.html test. The fix adds
viewport.refresh() methods to explicitly satisfy preconditions for every
method that does reads from viewport control model.

BUG=390204
TBR=vsevik

Review URL: https://codereview.chromium.org/370223004

git-svn-id: svn://svn.chromium.org/blink/trunk@177589 bbb929c8-8fbe-4397-9dbb-9b2b20218538