Performance/FetchingRemoteData: various sniff improvements

[jrfnl]

Performance/FetchingRemoteData: extend AbstractFunctionParameterSniff

As things were, the determination of whether or not a T_STRING is a call to the global PHP native str_replace() function was severely flawed.

By switching the sniff over to be based on the WordPressCS AbstractFunctionParameterSniff class, this flaw is mitigated.

Includes adding a slew of additional tests, some of which (line 8 - 13, 28, 37, 45) are specific to the flaw being addressed in this commit.

Additionally, the tests have been made more comprehensive and varied by:

• Testing against false positives for calls to methods or namespaced function calls (= the issue being addressed in this PR).
• Testing against false positives for attribute class using the same name as the function.
• Ensure function import use statements are not flagged. We're not interested in those.
• Adding more variations to the pre-existing tests:
  • Non-lowercase function call(s).
  • Fully qualified function calls.
  • Use PHP 7.3+ trailing comma's in a few function calls.
  • Use both single quoted as well as double quoted text strings in the tests.
  • Use other non-plain-text tokens in the passed parameter to test the FileGetContentsUnknown warning, which was previously untested.
  • Multi-line function call.
  • Comments in function call.

Performance/FetchingRemoteData: add tests for PHP 5.6 arg unpacking and PHP 8.0 named args

Both are already handled correctly after the switch to the WordPressCS AbstractFunctionParameterSniff class.

Performance/FetchingRemoteData: add support for handling PHP 8.1 first class callables

As first class callables will result in the function being called, but without us knowing the passed parameters, I believe it is appropriate to flag the use of file_get_contents() as a first class callable under the FileGetContentsUnknown warning.

This commit implements this in a WPCS cross-version compatible manner.

Prior to WPCS 3.2.0, first class callables would be send to the process_no_parameters() method.
As of WPCS 3.2.0, they will be send to the dedicated process_first_class_callable() method.

Performance/FetchingRemoteData: bug fix - recognize use of DIR as local file

Unless people get really creative with ternaries and such, the use of __DIR__ within the parameter basically means that we know they are retrieving a local file and we can silently ignore the function call.

Includes test.

Performance/FetchingRemoteData: bug fix - examine all text string tokens in the parameter

As things were, only the first text string token in the parameter was being examined, which resulted in false negatives.

Includes test.

Performance/FetchingRemoteData: bug fix - false negative for compound parameters

As things were, if the parameter did contain a text string token and that text string token did not contain the text "://", the sniff would stay silent, even when the parameter contained additional non-text string tokens, which means we cannot reliably determine whether it is a local file or not.

This commit changes the order of the checks to first check if any of the text string tokens in the parameter contain the "://" text. If so, it will throw the (more informative) FileGetContentsRemoteFile warning.

If not, it will check if the parameter contained anything but text string related or empty tokens. If so, it will throw the (more generic) FileGetContentsUnknown warning.

Includes test.

Closes #531