Remove the patch applied to pass the test/fiddle/test_import.rb on PPC.
    
    In Ruby 3.0.3, a new logic with the hard-coded "libc.so.6" to detect glibc
    works on PPC, both Power 8 and 9.
    See <https://bugs.ruby-lang.org/issues/12666#note-13>.
    
    Note the logic also fixes the following error on a Power 9 environment where
    the path is `/lib64/glibc-hwcaps/power9/libc-2.28.so`.
    
    ```
    /builddir/build/BUILD/ruby-2.6.9/.ext/common/fiddle/import.rb:299:in `import_function': cannot find the function: strcpy() (Fiddle::DLError)
        from /builddir/build/BUILD/ruby-2.6.9/.ext/common/fiddle/import.rb:172:in `extern'
        from /builddir/build/BUILD/ruby-2.6.9/test/fiddle/test_import.rb:17:in `<module:LIBC>'
        from /builddir/build/BUILD/ruby-2.6.9/test/fiddle/test_import.rb:10:in `<module:Fiddle>'
        from /builddir/build/BUILD/ruby-2.6.9/test/fiddle/test_import.rb:9:in `<top (required)>'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:958:in `require'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:958:in `block in non_options'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:952:in `each'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:952:in `non_options'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:64:in `process_args'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:130:in `process_args'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:1136:in `process_args'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:1141:in `run'
        from /builddir/build/BUILD/ruby-2.6.9/test/lib/test/unit.rb:1148:in `run'
        from ./test/runner.rb:33:in `<main>'
    ```