My workaround in an app that allows choosing of system sounds that may or may not have ANDROID_LOOP=true set involves checking the file and making a note as follows:

			window.resolveLocalFileSystemURL($('#soundfile').val(), function(entry){
				console.log('got file entry=',entry);
				entry.file(function(file){
					var reader = new FileReader();
					reader.onload = function(e) {
						this.result = this.result.substr(0,1024);
						if(this.result.toLowerCase().indexOf("android_loop=true")>0){
							console.log("ANDROID_LOOP=true detected!");
							settings.alarm_looper=true;
						} else if(settings.hasOwnProperty('alarm_looper')) delete settings.alarm_looper;
						// async, so..
						play_sound($('#soundfile').val());
						localStorage.setItem('settings',JSON.stringify(settings));
					}
					reader.readAsText(file);
				});
			}, function(e){
				console.log('failed to get file e=',e);
				if(settings.hasOwnProperty('alarm_looper')) delete settings.alarm_looper;
			});

Then I use a setInterval that detects duration to play the sound:

	sound_start=new Date().getTime();
	media1.play({ numberOfLoops: 1 });
	// hack for bug where files with ANDROID_LOOP=true always loop
	if(settings.alarm_looper){
		sound_end=null;
		if(!handle.hasOwnProperty('media')) handle.media=setInterval(function(){
			// wait until media gives us the duration..
			if(media1._duration==-1){
				console.log('media1._duration=-1, interval return');
				return;
			} else if(sound_end===null) sound_end=Math.round(sound_start+(media1._duration*1000)-40);

			var now=new Date().getTime();
			if(now>=sound_end){
				console.log('now>=sound_end '+now+'>='+sound_end+' killing media');
				if(media1!=null) media1.release();
				if(handle.hasOwnProperty('media')){
					clearInterval(handle.media);
					delete handle.media;
				}
				sound_end=null;
			}
		}, 50);
	}