Fix function scoping issue

Fix function scoping issue

The parser has special behavior with respect to the bindings
of inner functions in sloppy mode which are not at the top
level of scopes. This behavior should be turned off when the
--harmony-sloppy-function flag is set, as lexical scoping
rules are used instead. Previously, the incorrect flag
--harmony-sloppy was used, resulting in a crashing bug.

BUG=chromium:520029
LOG=Y
R=adamk

Review URL: https://codereview.chromium.org/1303033003

Cr-Commit-Position: refs/heads/master@{#30315}