[HTML5] Fix audio buffer size and latency hint.

The size of the audio buffer was incorrectly doubled when creating the
script processor.
latencyHint is expressed in seconds, not milliseconds.
Additionally, on some browsers it actually affect the performance and
stability of the audio driver.
For this reason it has been completely disabled (interactive) and a not
has been left for future reference.

platform/javascript/audio_driver_javascript.cpp

@@ -100,7 +100,7 @@ Error AudioDriverJavaScript::init() {
 	int latency = GLOBAL_GET("audio/output_latency");
 
 	channel_count = godot_audio_init(mix_rate, latency);
-	buffer_length = closest_power_of_2((latency * mix_rate / 1000) * channel_count);
+	buffer_length = closest_power_of_2(latency * mix_rate / 1000);
 	buffer_length = godot_audio_create_processor(buffer_length, channel_count);
 	if (!buffer_length) {
 		return FAILED;

platform/javascript/native/library_godot_audio.js

@@ -47,7 +47,7 @@ var GodotAudio = {
 	godot_audio_init: function(mix_rate, latency) {
 		GodotAudio.ctx = new (window.AudioContext || window.webkitAudioContext)({
 			sampleRate: mix_rate,
-			latencyHint: latency
+			// latencyHint: latency / 1000 // Do not specify, leave 'interactive' for good performance.
 		});
 		return GodotAudio.ctx.destination.channelCount;
 	},