Fixed #69195, #56821
* ecore.cs (ResolveBoolean): Tiny refactoring.
* expression.cs (Binary.DoResolve): Add warning 429 and skipping
of right expression resolving when left is false constant and
operator is LogicalAnd OR true constant and operator is LogicalOr.
* statement.cs (ResolveUnreachable): Always reports warning.
svn path=/trunk/mcs/; revision=37173