RFR: JDK-8289541 : Update ICU4C to 71.1

[Hima Bindu Meda]

Updated icu to v71.1.
Verified build and sanity testing on windows,Mac and Linux.
Removed icu directory from Source/WTF, as the functionality is already provided by Source/ThirdParty/icu

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Commit messages:
 - Update file permission for rbbicst.pl
 - update file permission
 - Remove tabs
 - whitespace corrections
 - Remove white spaces
 - Update icu version and checksum
 - Update icu to v71-1

Changes: https://git.openjdk.org/jfx/pull/893/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=893&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289541
  Stats: 152378 lines in 757 files changed: 11009 ins; 123550 del; 17819 mod
  Patch: https://git.openjdk.org/jfx/pull/893.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/893/head:pull/893

PR: https://git.openjdk.org/jfx/pull/893