inventory_hostnames lookup plugin -> 100% coverage (#70628)

Change:
- Add tests to get inventory_hostnames up to 100% coverage.

Test Plan:
- CI

Signed-off-by: Rick Elrod <rick@elrod.me>

test/integration/targets/lookup_inventory_hostnames/inventory

@@ -1,6 +1,18 @@
+nogroup01
+nogroup02
+nogroup03
+
 [group01]
 test01
 test05
 test03
 test02
 test04
+
+[group02]
+test03
+test04
+test200
+test201
+test203
+test204

test/integration/targets/lookup_inventory_hostnames/main.yml

@@ -4,10 +4,18 @@
   tasks:
   - set_fact:
       hosts_a: "{{ lookup('inventory_hostnames', 'group01', wantlist=true) }}"
-
-  - set_fact:
       hosts_b: "{{ groups['group01'] }}"
+      exclude: "{{ lookup('inventory_hostnames', 'group01:!test03', wantlist=true) }}"
+      intersect: "{{ lookup('inventory_hostnames', 'group01:&group02', wantlist=true) }}"
+      nogroup: "{{ lookup('inventory_hostnames', 'nogroup01', wantlist=true) }}"
+      doesnotexist: "{{ lookup('inventory_hostnames', 'doesnotexist', wantlist=true) }}"
+      all: "{{ lookup('inventory_hostnames', 'all', wantlist=true) }}"
 
   - assert:
       that:
         - hosts_a == hosts_b
+        - "'test03' not in exclude"
+        - intersect == ['test03', 'test04']
+        - nogroup == ['nogroup01']
+        - doesnotexist == []
+        - all|length == 12