Tell the register allocator the value is not overwritten.  Never use
temporary registers on ia32, avoid them on x64 and ARM.  Restore the
original copyright date on assembler.cc.

R=fschneider@chromium.org
BUG=v8:1870
TEST=

Review URL: http://codereview.chromium.org/8965038

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10280 ce2b1a6d-e550-0410-aec6-3dcde31c8c00