Add tests for SOUND and PLAY "MB"

These tests were intended to be added by #171, but the Linux build was
having problems. The issues with the build have since been resolved so
the tests are getting added back in.

Fixes: #173

tests/compile_tests/audio_handle_test/handle_test.bas

@@ -0,0 +1,22 @@
+Option _Explicit
+$Console
+$ScreenHide
+_Dest _Console
+
+' Try to open a non-existent file
+Dim handle As Long
+
+handle = _SndOpen("dummy.flac")
+Print handle
+If Not handle Then
+    Print "This failure was expected!"
+End If
+
+
+handle = _SndCopy(handle)
+Print handle
+If Not handle Then
+    Print "So was this!"
+End If
+
+System

tests/compile_tests/audio_handle_test/handle_test.output

@@ -0,0 +1,4 @@
+ 0 
+This failure was expected!
+ 0 
+So was this!

tests/compile_tests/audio_sound_test/sound_test.bas

@@ -0,0 +1,45 @@
+Option _Explicit
+$Console
+$ScreenHide
+_Dest _Console
+
+Dim As Long i, note, duration
+Dim word As String
+Dim As Double t, ct, d1, d2
+
+Play "mb"
+
+t = Timer
+For i = 1 To 34
+    Read note, duration, word
+    Sound note, duration: Print word$;
+Next
+Print
+ct = Timer
+If t > ct Then t = t - 86400
+d1 = ct - t
+
+Restore
+Play "mf"
+
+t = Timer
+For i = 1 To 34
+    Read note, duration, word
+    Sound note, duration: Print word$;
+Next
+Print
+ct = Timer
+If t > ct Then t = t - 86400
+d2 = ct - t
+
+If d2 - d1 > 5 Then
+    Print "Foreground playback always takes longer to complete than background playback."
+End If
+
+System
+
+Data 392,8,"My ",659,8,"Bon-",587,8,"nie ",523,8,"lies ",587,8,"O-",523,8,"Ver ",440,8,"the "
+Data 392,8,"O-",330,32,"cean ",392,8,"My ",659,8,"Bon-",587,8,"nie ",523,8,"lies "
+Data 523,8,"O-",494,8,"ver ",523,8,"the ",587,40,"sea ",392,8,"My ",659,8,"Bon-",587,8,"nie"
+Data 523,8," lies ",587,8,"O-",523,8,"ver ",440,8,"the ",392,8,"O-",330,32,"cean ",392,8,"Oh "
+Data 440,8,"bring ",587,8,"back ",523,8,"my ",494,8,"Bon-",440,8,"nie ",494,8,"to ",523,32,"me..!"

tests/compile_tests/audio_sound_test/sound_test.output

@@ -0,0 +1,3 @@
+My Bon-nie lies O-Ver the O-cean My Bon-nie lies O-ver the sea My Bon-nie lies O-ver the O-cean Oh bring back my Bon-nie to me..!
+My Bon-nie lies O-Ver the O-cean My Bon-nie lies O-ver the sea My Bon-nie lies O-ver the O-cean Oh bring back my Bon-nie to me..!
+Foreground playback always takes longer to complete than background playback.