Remove platform-specific dead code for KeyedStores

R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22745003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16227 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Promote ArrayBuffer, DataView and typed arrays to non-experimental.

The primary reason for this change is to bake these guys into the
snapshot.

Flag definitions (--harmony-typed-arrays, --harmony-array-buffer) are
still there so that Blink does not complain, but they are noop and
default to true.

R=mstarzinger@chromium.org
BUG=270527

Committed: https://code.google.com/p/v8/source/detail?r=16137

Review URL: https://codereview.chromium.org/22390008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16228 ce2b1a6d-e550-0410-aec6-3dcde31c8c00