8328286: Enhance HTTP client

...base/share/classes/java/net/doc-files/net-properties.html

src/java.base/share/classes/sun/net/www/MessageHeader.java

.../classes/sun/net/www/protocol/http/HttpURLConnection.java

src/java.base/share/conf/net.properties

...et.http/share/classes/jdk/internal/net/http/Exchange.java

...hare/classes/jdk/internal/net/http/Http1HeaderParser.java

.../share/classes/jdk/internal/net/http/Http2ClientImpl.java

.../share/classes/jdk/internal/net/http/Http2Connection.java

...p/share/classes/jdk/internal/net/http/HttpClientImpl.java

.../share/classes/jdk/internal/net/http/HttpRequestImpl.java

...e/classes/jdk/internal/net/http/ResponseBodyHandlers.java

....net.http/share/classes/jdk/internal/net/http/Stream.java

...e/classes/jdk/internal/net/http/common/HeaderDecoder.java

...ttp/share/classes/jdk/internal/net/http/common/Utils.java

...tp/share/classes/jdk/internal/net/http/hpack/Decoder.java

...classes/jdk/internal/net/http/hpack/DecodingCallback.java

...tp/share/classes/jdk/internal/net/http/hpack/Encoder.java

....httpserver/share/classes/sun/net/httpserver/Request.java

...server/share/classes/sun/net/httpserver/ServerConfig.java

...dk/java/net/httpclient/http2/PushPromiseContinuation.java