Clean up VMState a little bit.

R=svenpanne@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/14139033

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14421 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fixed HUnaryMathOperation regarding its possible operations.

Review URL: https://codereview.chromium.org/14333013

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14422 ce2b1a6d-e550-0410-aec6-3dcde31c8c00