The tests now compile and won't panic for unexpected return values.
We need a recent-enough version of the mutan compiler because of
the new JUMPDEST requirements. Skip some tests if the installed mutan
version is too old. The debug VM test still fails, probably because
of an implementation bug.
Standard VM should be about 10x faster than the debug VM. Some error
checking has been removed, all of the log statements and therefor quite
some unnecessary if-statements.