assert() refinement
- assert with two arguments allowed
- assert can be called indirectly
- assert is not treated as a keyword by parser
- assert optimization (does not cause unoptimized locals)

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C5456
Expression.TypeInfoValue

git-tfs-id: [http://falcon:8080/tfs/Projects]$/Phalanger/Main;C5475