hg: jdk/submit: 8245307: Update ExchangeImpl to use thread safe DateTimeFormatter

[daniel.fuchs at oracle.com]

Changeset: 2aa12b19f2f3
Author:    ryadav
Date:      2020-06-15 16:26 +0100
URL:       https://hg.openjdk.java.net/jdk/submit/rev/2aa12b19f2f3

8245307: Update ExchangeImpl to use thread safe DateTimeFormatter
Summary: The fix updates sun.net.httpserver.ExchangeImpl to use thread safe DateTimeFormatter for response headers, this replaces DateFormat that was using ThreadLocal.
Reviewed-by: dfuchs, alanb, chegar

! src/jdk.httpserver/share/classes/sun/net/httpserver/ExchangeImpl.java
+ test/jdk/com/sun/net/httpserver/DateFormatterTest.java