RFR: 8211990: DateTimeException thrown when calculating duration between certain dates

[naoto.sato at oracle.com]

Hello,

Please review the fix to the following issue:

https://bugs.openjdk.java.net/browse/JDK-8211990

The proposed changeset is located at:

https://cr.openjdk.java.net/~naoto/8211990/webrev.00/

The DateTimeException was thrown due to unconditional conversion beyond 
the valid range of the internal LocalDateTime value. If it happens, 
normalize two instants with the offset of "start" instant. The same kind 
of exception is observed with ZonedDateTime.until(), which is also fixed 
in this changeset.

Naoto