RFR: JDK-8289541 : Update ICU4C to 71.1 [v6]

[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

Hima Bindu Meda has updated the pull request incrementally with one additional commit since the last revision:

  Space corrections

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Changes:
  - all: https://git.openjdk.org/jfx/pull/893/files
  - new: https://git.openjdk.org/jfx/pull/893/files/22c8e530..88301d54

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=893&range=05
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=893&range=04-05

  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 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