Add HTML snapshots of failing tests to HTML Report

* #5568 Missing HTML snapshots of failing PhpBrowser acceptance tests in HTML Report after update to v3.0.x

Bug was introduced via https://github.com/Codeception/Codeception/commit/cca5463cdefd12120783bca94081496f02f226e9

Fix: In addition to saving the PhpBrowser as report 'response', also again save it as report 'html' (which is then picked up by HTML report generator in https://github.com/Codeception/phpunit-wrapper/blob/04a825f35706fce8be1c51bb975c20b450aa4571/src/ResultPrinter/HTML.php#L139-L150)

Add reproducer test case in RunCest based on new "phpbrowser_html_report" test suite

* #5568 Missing HTML snapshots of failing PhpBrowser acceptance tests in HTML Report after update to v3.0.x

Add (actually generated) "_support/AcceptanceTester.php" like by other Codeception test (suites)

* #5568 Missing HTML snapshots of failing PhpBrowser acceptance tests in HTML Report after update to v3.0.x

Fix: Since using URL 'http://127.0.0.1:8000' (like in other test suites) does not work in CI (see https://ci.appveyor.com/project/DavertMik/codeception/builds/27522016) => let's naively try another rather very reliable URL, namely 'https://www.google.com'

* #5568 Missing HTML snapshots of failing PhpBrowser acceptance tests in HTML Report after update to v3.0.x

Fix: Test failed due to hard-coded '/' in expected absolute filename output (see https://ci.appveyor.com/project/DavertMik/codeception/builds/27522721) => use platform dependent DIRECTORY_SEPARATOR when building the expected absolute filename

* #5568 Missing HTML snapshots of failing PhpBrowser acceptance tests in HTML Report after update to v3.0.x

Fix: Failed again in M$ Windows CI because not the full output uses platform dependent directory separator (see https://ci.appveyor.com/project/DavertMik/codeception/builds/27523181) => make the test hopefully succeed at long last by also hard-coding the relative report path