Fix unit tests to enable to run CacheResourceFileTest.php on Windows

[matsuo]

This PR fixes unit tests to enable to run CacheResourceFileTest.php on Windows. (Related PR: #1046 )
Some unit tests in CacheResourceFileTest.php now take the directory separator of Windows into account.

Test Results after modification:

> php .\vendor\phpunit\phpunit\phpunit --filter=CacheResourceFileTest
PHPUnit 8.5.39 by Sebastian Bergmann and contributors.

...............................................................   63 / 63 (100%)

Time: 56.96 seconds, Memory: 18.00 MB

OK (63 tests, 258 assertions)

Current Test Results:
(from #1046 (comment) )

1) CacheResourceFileTest::testGetCachedFilepathSubDirs
Failed asserting that 'D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\cache\ca\25\46\ca2546820bc1a72783da84062884d71d8e3c1ff4_helloworld.tpl.php' matches PCRE pattern "/.*\/([a-f0-9]{2}\/){3}.*.php/".

D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\CacheResourceFileTest.php:41

2) CacheResourceFileTest::testGetCachedFilepathCacheId
Failed asserting that 'D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\cache\foo\bar\ca\25\46\ca2546820bc1a72783da84062884d71d8e3c1ff4_helloworld.tpl.php' matches PCRE pattern "/.*\/foo\/bar\/([a-f0-9]{2}\/){3}.*.php/".

D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\CacheResourceFileTest.php:54

3) CacheResourceFileTest::testGetCachedFilepathCompileId
Failed asserting that 'D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\cache\blar\ca\25\46\ca2546820bc1a72783da84062884d71d8e3c1ff4_helloworld.tpl.php' matches PCRE pattern "/.*\/blar\/([a-f0-9]{2}\/){3}.*.php/".

D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\CacheResourceFileTest.php:66

4) CacheResourceFileTest::testGetCachedFilepathCacheIdCompileId
Failed asserting that 'D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\cache\foo\bar\blar\ca\25\46\ca2546820bc1a72783da84062884d71d8e3c1ff4_helloworld.tpl.php' matches PCRE pattern "/.*\/foo\/bar\/blar\/([a-f0-9]{2}\/){3}.*.php/".

D:\a\smarty\smarty\tests\UnitTests\CacheResourceTests\File\CacheResourceFileTest.php:78