Fix public int read() throws IOException method exceeds the limit of length (#9306)

Motivation:

buffer.isReadable() should not be used to limit the amount of data that can be read as the amount may be less then was is readable.

Modification:

- Use  available() which takes the length into account
- Add unit test

Result:

Fixes https://github.com/netty/netty/issues/9305

buffer/src/main/java/io/netty/buffer/ByteBufInputStream.java

@@ -165,7 +165,8 @@ public class ByteBufInputStream extends InputStream implements DataInput {
 
     @Override
     public int read() throws IOException {
-        if (!buffer.isReadable()) {
+        int available = available();
+        if (available == 0) {
             return -1;
         }
         return buffer.readByte() & 0xff;

buffer/src/test/java/io/netty/buffer/ByteBufStreamTest.java

@@ -212,4 +212,39 @@ public class ByteBufStreamTest {
         assertEquals(charCount, count);
         in.close();
     }
+
+    @Test
+    public void testRead() throws Exception {
+        // case1
+        ByteBuf buf = Unpooled.buffer(16);
+        buf.writeBytes(new byte[]{1, 2, 3, 4, 5, 6});
+
+        ByteBufInputStream in = new ByteBufInputStream(buf, 3);
+
+        assertEquals(1, in.read());
+        assertEquals(2, in.read());
+        assertEquals(3, in.read());
+        assertEquals(-1, in.read());
+        assertEquals(-1, in.read());
+        assertEquals(-1, in.read());
+
+        buf.release();
+        in.close();
+
+        // case2
+        ByteBuf buf2 = Unpooled.buffer(16);
+        buf2.writeBytes(new byte[]{1, 2, 3, 4, 5, 6});
+
+        ByteBufInputStream in2 = new ByteBufInputStream(buf2, 4);
+
+        assertEquals(1, in2.read());
+        assertEquals(2, in2.read());
+        assertEquals(3, in2.read());
+        assertEquals(4, in2.read());
+        assertNotEquals(5, in2.read());
+        assertEquals(-1, in2.read());
+
+        buf2.release();
+        in2.close();
+    }
 }