Summary: to keep the default behavior of ZOS unchanged, if ze extra time not explicitly set
Reviewed-by: alanb, ksrini

6303183: Support NTFS and Unix-style timestamps for entries in Zip files
7012856: (zipfs) Newly created entry in zip file system should set all file times non-null values.
7012868: (zipfs) file times of entry in zipfs should always be the same regardless of TimeZone.
Summary: to add suuport of Info-ZIP extended timestamp in extra data fields
Reviewed-by: martin, alanb

Reviewed-by: darcy, weijun