* testsuite/README: Change "UNSUPPORTED" tag to "FEATURE".

* testsuite/README: Change "UNSUPPORTED" tag to "FEATURE".
* testsuite/runtest (run_applet_testcase): Likewise.
* testsuite/cp/cp-preserves-hard-links: Likewise.
* testsuite/grep/egrep-supports-extended-regexps: Likewise.
* testsuite/grep/grep-is-also-egrep: Likewise.
* testsuite/tar/tar-archives-multiple-files: Likewise.
* testsuite/tar/tar-handles-empty-include-and-non-empty-exclude-list:
  Likewise.
* testsuite/tar/tar-handles-exclude-and-extract-lists: Likewise.
* testsuite/tar/tar-handles-nested-exclude: Likewise.