audio: Provide code for parsing surround sound config from XML

The main change is to convert the result of parsing from XSDC
types to AIDL, and add a VTS test for IConfig.getSurroundSoundConfig.

Extra changes:
  - add 'Unchecked' suffix to conversion functions that do not
    wrap the result into ConversionResult;
  - enable more compile-time checks for the default AIDL service,
    fix issues found.

Bug: 205884982
Test: atest VtsHalAudioCoreTargetTest
Change-Id: Icf578b8d28647e6355ed5328599c77d2ca1234f9
diff --git a/audio/aidl/default/main.cpp b/audio/aidl/default/main.cpp
index af71aa8..12c0c4b 100644
--- a/audio/aidl/default/main.cpp
+++ b/audio/aidl/default/main.cpp
@@ -64,6 +64,7 @@
     auto modules = {createModule(Module::Type::DEFAULT, "default"),
                     createModule(Module::Type::R_SUBMIX, "r_submix"),
                     createModule(Module::Type::USB, "usb")};
+    (void)modules;
 
     ABinderProcess_joinThreadPool();
     return EXIT_FAILURE;  // should not reach