[DevTools] Disable touch emulation on devices with touch input.

Previously, we disabled it on mobile devices, which was not accurate.

BUG=337142

Review URL: https://codereview.chromium.org/243233002

git-svn-id: svn://svn.chromium.org/blink/trunk@172074 bbb929c8-8fbe-4397-9dbb-9b2b20218538