Fix ARM build for gcc-4.6.

Fix ARM build for gcc-4.6.
This is based on Peter Varga's work in http://codereview.chromium.org/7708004/
but with a different solution for the Operand(0) int/pointer ambiguity.
Committed: http://code.google.com/p/v8/source/detail?r=8998

[Peter Varga, 2011-08-23 09:49:38]

You should remove unused variables from the code-stubs-arm.cc too:
src/arm/code-stubs-arm.cc:2427:12: error: variable 'scratch2' set but not used
src/arm/code-stubs-arm.cc:3113:20: error: variable 'heap_number_map' set but not
used

Anyway, this solution is ok for me. Thanks.

[Erik Corry, 2011-08-23 10:07:07]

Thanks Peter, I updated the change.

[William Hesse, 2011-08-23 11:51:17]

LGTM.