IDL compiler: Typed arrays for methods

Code tweaks, tests added for types actually used.

BUG=239771
NOTRY=true

Review URL: https://codereview.chromium.org/51693003

git-svn-id: svn://svn.chromium.org/blink/trunk@160902 bbb929c8-8fbe-4397-9dbb-9b2b20218538