Inline the Array.isArray builtin during typed lowering, which generates
ideal code for the common case (non-JSProxy arg), and use the existing
%ArrayIsArray runtime function for the JSProxy case just like in baseline.

BUG=v8:5267
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2719023002
Cr-Commit-Position: refs/heads/master@{#43453}