HttpRequest: Don't wait for socket to be readable

The socket is a blocking one, which means Read() will block unless data
is available, thus WaitForReadable() is useless in this context.

Testing also shows a 2x performance increase from removing this call due
to poll() performance being botched when KDEBUG_LEVEL >= 2.

Change-Id: I3170f865e961112b420c1548726bb6fd38e94cb2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3078
Reviewed-by: waddlesplash <[email protected]>

src/kits/network/libnetapi/HttpRequest.cpp

@@ -584,7 +584,6 @@ BHttpRequest::_MakeRequest()
 
 	while (!fQuit && !(receiveEnd && parseEnd)) {
 		if ((!receiveEnd) && (fInputBuffer.Size() == previousBufferSize)) {
-			fSocket->WaitForReadable();
 			BStackOrHeapArray<char, 4096> chunk(kHttpBufferSize);
 			bytesRead = fSocket->Read(chunk, kHttpBufferSize);