Respect all informational status codes. (netty#9712)

Motivation:

HTTP 102 (WebDAV) is not correctly treated as an informational response

Modification:

Delegate all `1XX` status codes to superclass, not just `100` and `101`.

Result:

Supports WebDAV response.
Removes a huge maintenance [headache](line/armeria#2210) in Armeria which has forked the class for these features

codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java

@@ -223,8 +223,8 @@ private void decrement(Object msg) {
         @Override
         protected boolean isContentAlwaysEmpty(HttpMessage msg) {
             final int statusCode = ((HttpResponse) msg).status().code();
-            if (statusCode == 100 || statusCode == 101) {
-                // 100-continue and 101 switching protocols response should be excluded from paired comparison.
+            if (statusCode >= 100 && statusCode < 200) {
+                // An informational response should be excluded from paired comparison.
                 // Just delegate to super method which has all the needed handling.
                 return super.isContentAlwaysEmpty(msg);
             }

codec-http/src/test/java/io/netty/handler/codec/http/HttpClientCodecTest.java

@@ -332,6 +332,26 @@ public void testWebSocket00Response() {
         assertThat(ch.readInbound(), is(nullValue()));
     }
 
+    @Test
+    public void testWebDavResponse() {
+        byte[] data = ("HTTP/1.1 102 Processing\r\n" +
+                       "Status-URI: Status-URI:http://status.com; 404\r\n" +
+                       "\r\n" +
+                       "1234567812345678").getBytes();
+        EmbeddedChannel ch = new EmbeddedChannel(new HttpClientCodec());
+        assertTrue(ch.writeInbound(Unpooled.wrappedBuffer(data)));
+
+        HttpResponse res = ch.readInbound();
+        assertThat(res.protocolVersion(), sameInstance(HttpVersion.HTTP_1_1));
+        assertThat(res.status(), is(HttpResponseStatus.PROCESSING));
+        HttpContent content = ch.readInbound();
+        // HTTP 102 is not allowed to have content.
+        assertThat(content.content().readableBytes(), is(0));
+        content.release();
+
+        assertThat(ch.finish(), is(false));
+    }
+
     @Test
     public void testMultipleResponses() {
         String response = "HTTP/1.1 200 OK\r\n" +