AIDL effect: Refine some implementation and test logic.

Bug: 238913361
Test: atest VtsHalAudioEffectTargetTest
Change-Id: I5a9bb542872de6c5700fa6b14e124e9b9e206da6
diff --git a/audio/aidl/default/EffectMain.cpp b/audio/aidl/default/EffectMain.cpp
index b30f2e7..3219dd6 100644
--- a/audio/aidl/default/EffectMain.cpp
+++ b/audio/aidl/default/EffectMain.cpp
@@ -23,7 +23,7 @@
 int main() {
     // This is a debug implementation, always enable debug logging.
     android::base::SetMinimumLogSeverity(::android::base::DEBUG);
-    ABinderProcess_setThreadPoolMaxThreadCount(1);
+    ABinderProcess_setThreadPoolMaxThreadCount(0);
 
     auto effectFactory =
             ndk::SharedRefBase::make<aidl::android::hardware::audio::effect::Factory>();