Remove WebInspector.HeapSnapshotArraySlice

This is exact copy of r169554 with a fix for inpsector protocol tests.

Uin32Array already has subarray method that returns a new view for the same array buffer.

BUG=None
TBR=alph@chromium.org

Review URL: https://codereview.chromium.org/197533009

git-svn-id: svn://svn.chromium.org/blink/trunk@169639 bbb929c8-8fbe-4397-9dbb-9b2b20218538