Fix handling of Integer32 in HLoadNamedField and HStoreNamedField on x64.
Fix handling of Integer32 in HLoadNamedField and HStoreNamedField on x64.

The current implementation of Integer32 named loads and stores
is broken on x64.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/23548039

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@16750 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh