range index is not enabled when `&&` is used with executable-model

[tkobayas]

When a constraint is like age >= 0 && age < 20, executable-model doesn't split the constraint into two constraints, so it doesn't enable range index. It only affects the performance (it's enabled when more than 9 alpha nodes for the same field by default), not the rule behaviour.

age >= 0, age < 20 doesn't have this issue.

AlphaNodeRangeIndexingTest

    public void testSurroundingRange(KieBaseTestConfiguration kieBaseTestConfiguration) {
        final String drl =
                "package org.drools.compiler.test\n" +
                           "import " + Person.class.getCanonicalName() + "\n" +
                           "rule test1\n when\n" +
                           "   Person( age >= 0 && age < 20 )\n" +
                           "then\n end\n" +
                           "rule test2\n when\n" +
                           "   Person( age >= 20 && age < 40 )\n" +
                           "then\n end\n" +
                           "rule test3\n when\n" +
                           "   Person( age >= 40 && age < 60 )\n" +
                           "then\n end\n";

        final KieBase kbase = createKieBaseWithRangeIndexThresholdValue(kieBaseTestConfiguration, drl, 3);
        final KieSession ksession = kbase.newKieSession();

        assertSinks(kieBaseTestConfiguration, kbase, Person.class, 3, 3, 0, 3);

        ksession.insert(new Person("John", 18));
        int fired = ksession.fireAllRules();
        assertThat(fired).isEqualTo(1);

        ksession.insert(new Person("Paul", 60));
        fired = ksession.fireAllRules();
        assertThat(fired).isEqualTo(0);
    }