RFR: 8331975: Enable case-insensitive check in ccache and keytab entry lookup [v3]

[Weijun Wang]

> Add a new system property to control the name comparison in keytab and ccache entry lookup.

Weijun Wang has updated the pull request incrementally with two additional commits since the last revision:

 - remove commented out code but leave comment
 - fast fail and no need to check null

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/19216/files
  - new: https://git.openjdk.org/jdk/pull/19216/files/1263ae13..c74e6450

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19216&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19216&range=01-02

  Stats: 18 lines in 1 file changed: 0 ins; 5 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/19216.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19216/head:pull/19216

PR: https://git.openjdk.org/jdk/pull/19216