ES6 symbols: refine test for getOwnPropertyNames

R=mstarzinger@chromium.org
BUG=v8:2158

Review URL: https://codereview.chromium.org/12432005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13866 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Harden Function()'s parsing of function literals.

R=rossberg@chromium.org
BUG=v8:2470
TEST=mjsunit/regress/regress-2470

Review URL: https://codereview.chromium.org/12613007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13867 ce2b1a6d-e550-0410-aec6-3dcde31c8c00