HeaderInfo object, and modifying the operator in the loop condition.
The "additional emptiness condition" is no longer necessary with this.
The open/closed property was removed from HeaderInfo in an earlier
commit, but bringing it back in to simplify the loop building makes
more sense.
Also expanded tests for evaluation order of range bounds.
do-while with enclosing "not empty" check).
Also do not add additional "not empty" condition for `until` loops when
the given bound is a constant != MIN_VALUE.
All bytecode text tests are run with stdlib in the classpath and only
for JVM backend, therefore directives WITH_RUNTIME, TARGET_BACKEND,
IGNORE_BACKEND are not needed
NB: for-in-until loop is generated as precondition loop, because the
corresponding range is right-exclusive (and thus we have no problems
with integer overflows).
Mark Punzalan