The limit was originally added to avoid having large user-controlled constants
(variable indexes) in the code generated by full-codegen.

History behind this change:

The original CL for adding the limit was https://codereview.chromium.org/7003030
and at that time, the limit was 32767.

Reason for adding the limit (in CL comments): "The motivation behind this change
is to avoid large user controlled constants in the code. The slot_operand used
in the IA32 full code generator uses a relative load where the local index is an
(negative) immediate."

The limit was then bumped to 65535 by https://codereview.chromium.org/10965063
and to 131071 by https://codereview.chromium.org/11099063.

R=dcarney@chromium.org, svenpanne@chromium.org, jkummerow@chromium.org, rossberg@chromium.org
BUG=v8:3205
LOG=Y

Review URL: https://codereview.chromium.org/206143004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20126 ce2b1a6d-e550-0410-aec6-3dcde31c8c00