WB_IsMethodCompilable ignores compiler directives

Calling WB::isMethodCompilable(m) for a method m that cannot be compiled by either C1 or C2 due to a compiler directive (compileonly not including m, or excluding m) should return false. This, however, is not always the case since the ExcludeOption compiler directive is only evaluated lazily upon a compilation attempt. If m was not attempted to be compiled by C1 and/or C2, Method::is_not_compilable() returns false and thus WB::isMethodCompilable(m) returns true.

This should be fixed by making WB_IsMethodCompilable aware of the ExcludeOption compiler directive.