Audio VTS: Suppress empty parameter list failures

GTest has introduced a check verifying that the parameter list
for TEST_P tests isn't empty. Having an empty parameter list
isn't actually a problem when the VTS test runs on a device
that lacks the corresponding HAL version.

Bug: 161758075
Test: atest VtsHalAudioV4_0TargetTest
Test: atest VtsHalAudioV5_0TargetTest
Test: atest VtsHalAudioV6_0TargetTest
Test: atest VtsHalAudioEffectV4_0TargetTest
Test: atest VtsHalAudioEffectV5_0TargetTest
Test: atest VtsHalAudioEffectV6_0TargetTest
Change-Id: Ib2a017b74f69b1608d8985f403e9b2a8e54b8311