Rename layout test filenames with "cat" and "hat" combinators

Rename test filenames with obsolete "cat" (^) and "hat" (^^) combinators
to ones that conforming to the current spec (e.g. /deep/ (deep combinator),
::shadow (shadow pseudo element), :host (host pseudo class).

Changes are filenames only and no functional change in
actual tests.

BUG=none
TEST=Run affected layout tests.

Review URL: https://codereview.chromium.org/289923004

git-svn-id: svn://svn.chromium.org/blink/trunk@174074 bbb929c8-8fbe-4397-9dbb-9b2b20218538