Revert "ARM: Improve register allocation and constraints."

Revert "ARM: Improve register allocation and constraints."

This reverts r8381.

It was causing Mozilla test mozilla/ecma/Date/15.9.3.8-5 to fail and Sputnik tests S15.9.3.1_A5_T5, S15.9.3.1_A5_T1, S15.9.3.1_A5_T2, S15.9.3.1_A5_T4, S15.9.3.1_A5_T3 and S15.9.3.1_A5_T6 to timeout.

R=ager@chromium.org

BUG=none
TEST=mozilla/ecma/Date/15.9.3.8-5, S15.9.3.1_A5_T5, S15.9.3.1_A5_T1, S15.9.3.1_A5_T2, S15.9.3.1_A5_T4, S15.9.3.1_A5_T3 and S15.9.3.1_A5_T6

Committed: http://code.google.com/p/v8/source/detail?r=8397

[Mads Ager (chromium), 2011-06-23 11:52:41]

LGTM