Property reactive may cause pending activations to be removed

This is a simple all-DRL test case demonstrating that property reactive
may cause pending activations to be removed, depending on some
specific composition of the LHS:

declare Person
@propertyReactive
name : String
age : int
weight : int
end

rule kickoff
salience 100
when
then
Person p = new Person( "Joe", 20, 20 );
insert( p );
end

rule y
when
$p : Person(name == "Joe" )
then
modify($p)

{ setAge( 100 ) }

end

rule x
when
$p : Person(name == "Joe" )
then
modify($p)

{ setWeight( 100 ) }

end

rule z
salience -100
when
$p : Person()
then
System.out.println( $p );
if ($p.getAge() != 100 || $p.getWeight() != 100) throw new RuntimeException();
end