Audio Effects: Run more tests for LoudnessEnhancerEffect

Due to incorrect assumptions about test case inheritance
in GTests, LoudnessEnhancerEffect wasn't running tests
for methods of IEffect interface. The test code has been
restructured to fix that via proper parametrization.

Bug: 146149801
Test: atest VtsHalAudioEffectV5_0TargetTest
Test: atest VtsHalAudioEffectV6_0TargetTest
Change-Id: Ie366979880bfc3b7e95a02957451736d724f838f