Implement ES5 erratum: global declarations shadow inherited properties.

Implement ES5 erratum: global declarations shadow inherited properties.

I also discovered that our treatment of const declarations is inconsistent
when inside a global eval under 'with' (i.e., when created by
DeclareContextSlots). That is,

  var x;
  eval("const x = 9")

and

  var x;
  eval("with({}) const x = 9")

differ (the former assigns 9, the latter throws). This appears to be an
oversight from earlier changes to our const semantics (the latter shouldn't
throw either). Fixing this is a separate issue, though (and one that doesn't
seem quite worthwhile).

R=mstarzinger@chromium.org
BUG=v8:1991, 80591
TEST=

Committed: https://code.google.com/p/v8/source/detail?r=11333

[Michael Starzinger, 2012-04-16 11:32:30]

LGTM (just a few nits).

https://chromiumcodereview.appspot.com/10067010/diff/1/src/runtime.cc
File src/runtime.cc (right):

https://chromiumcodereview.appspot.com/10067010/diff/1/src/runtime.cc#newcode...
src/runtime.cc:1344: // If the local property exists, check that we can either
reconfigure it
This sentences is missing the "or" part of "either ... or" I think.

https://chromiumcodereview.appspot.com/10067010/diff/1/src/runtime.cc#newcode...
src/runtime.cc:1496: /*ERRATUM: no longer need to traverse the prototype
chain?*/
This looks like a leftover, should that be a TODO?

https://chromiumcodereview.appspot.com/10067010/diff/1/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://chromiumcodereview.appspot.com/10067010/diff/1/test/cctest/test-api.c...
test/cctest/test-api.cc:12433: // value does not shadow an existing property in
the prototype chain.
The whole comment no longer applies.

[rossberg, 2012-04-16 13:15:44]

https://chromiumcodereview.appspot.com/10067010/diff/1/src/runtime.cc
File src/runtime.cc (right):

https://chromiumcodereview.appspot.com/10067010/diff/1/src/runtime.cc#newcode...
src/runtime.cc:1344: // If the local property exists, check that we can either
reconfigure it
On 2012/04/16 11:32:30, Michael Starzinger wrote:
> This sentences is missing the "or" part of "either ... or" I think.

Done.

https://chromiumcodereview.appspot.com/10067010/diff/1/src/runtime.cc#newcode...
src/runtime.cc:1496: /*ERRATUM: no longer need to traverse the prototype
chain?*/
On 2012/04/16 11:32:30, Michael Starzinger wrote:
> This looks like a leftover, should that be a TODO?

Done.

https://chromiumcodereview.appspot.com/10067010/diff/1/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://chromiumcodereview.appspot.com/10067010/diff/1/test/cctest/test-api.c...
test/cctest/test-api.cc:12433: // value does not shadow an existing property in
the prototype chain.
On 2012/04/16 11:32:30, Michael Starzinger wrote:
> The whole comment no longer applies.

Done.