Switch to PPSSPP's assert functions (don't use the system's)

Core/Debugger/WebSocket/GPUBufferSubscriber.cpp

@@ -113,7 +113,7 @@ static bool StreamBufferToDataURI(DebuggerRequest &req, const GPUDebugBuffer &bu
 			req.ws->AddFragment(false, Base64Encode(ctx->buf, ctx->bufSize));
 			ctx->bufSize = 0;
 		}
-		assert(ctx->bufSize == 0 || length == 0);
+		_assert_(ctx->bufSize == 0 || length == 0);
 
 		// Save bytes that would result in padding for next time.
 		size_t toBuffer = length % 3;
@@ -241,7 +241,7 @@ static void GenericStreamBuffer(DebuggerRequest &req, std::function<bool(const G
 	if (!func(buf)) {
 		return req.Fail("Could not download output");
 	}
-	assert(buf != nullptr);
+	_assert_(buf != nullptr);
 
 	if (type == "base64") {
 		StreamBufferToBase64(req, *buf);