RFR: 8282293: Domain value for system property jdk.https.negotiate.cbt should be case-insensitive

[Sibabrata Sahoo]

Domain value for system property jdk.https.negotiate.cbt  is case-insensitive now. Included Test has been updated to address the change.

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Commit messages:
 - 8282293: Domain value for system property jdk.https.negotiate.cbt should be case-insensitive

Changes: https://git.openjdk.java.net/jdk/pull/7759/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7759&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282293
  Stats: 10 lines in 2 files changed: 7 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7759.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7759/head:pull/7759

PR: https://git.openjdk.java.net/jdk/pull/7759