According to ES5 10.4.2(3), eval calls of strict code always require
their own lexical and variable environment. For now we just add a new
scope when we parse the strict mode directive. The clean solution would
be to always have this sope present (even for global eval calls) and
adapt variable binding to cope with that.

R=rossberg@chromium.org
BUG=v8:1624
TEST=mjsunit/regress/regress-1624,test262/S10.4.2.1_A1

Review URL: https://chromiumcodereview.appspot.com/9703021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11057 ce2b1a6d-e550-0410-aec6-3dcde31c8c00