Endian changes, support 64bit big endian

These are some changes split off from https://codereview.chromium.org/422063005

frames-inl.h, frames.h
based on https://github.com/andrewlow/v8ppc/commit/05db7d2d714c44bd4e0b710fdaa51d34938aaa27
On 64bit big endian systems, the integer value is in the second slot, thus we need a new offset.

objects-inl.h, objects.h
based on https://github.com/andrewlow/v8ppc/commit/09b680b2af7412fe8fa5a3a01f1b8e29698d7797
Similarly, the hash slot is an integer field and we need to do the right thing on 64bit big endian systems

objects.cc
based on: https://github.com/andrewlow/v8ppc/commit/065742b0783b0705d9f9711198248a92bac11d85
Prettier printing of constant pools

test-strings.cc
based on:  https://github.com/andrewlow/v8ppc/commit/9889d60cd6e68e0d248c4a362ffdff0755b92aec
endian fixes

BUG=
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/551803004

Patch from Andrew Low <andrew_low@ca.ibm.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24365 ce2b1a6d-e550-0410-aec6-3dcde31c8c00