[9] RFR: 8151182: HttpHeaders.allValues should return unmodifiable List as per JavaDoc

[vaibhav x.choudhary]

Hi,

Please review :-

Review Link :- http://cr.openjdk.java.net/~ntv/vaibhav/JDK8151182/webrev.00/
Bug ID: https://bugs.openjdk.java.net/browse/JDK-8151182

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Thank You,
Vaibhav Choudhary
http://blogs.oracle.com/vaibhav