FileExcluder: Improve performance of isExcludedFromAnalysing

[dktapps]

I discovered this while debugging phpstan/phpstan#5825.

When analysing pmmp/PocketMine-MP@701a71a with a result cache + no unchanged files, I noticed that isExcludedFromAnalysing() took over 9% of the total time spent. I'm not sure why this is needed when result cache is used, but it became immediately obvious to me that there were performance gains to be had here.

Before analysis, an xdebug profiler snapshot showed that this method took 9% of the total CPU time and called isFnmatchPattern() over 124,000 times. This is pretty bad considering that PM doesn't use fnmatch patterns at all.
isFnmatchPattern() took about 2.7% time.

After the patch, this drops to about 1.9% for isExcludedFromAnalysis() and 0.1% for isFnmatchPattern(), with isFnmatchPattern() now being called only ~2,200 times.

In real numbers, this shaves off a fraction of a second of pre-analysis time when a result cache is used (at least on Windows).

[ondrejmirtes]

Thank you!

[dktapps]

I do have another suggestion that cuts it by another 10% or so (in my case), which is to use the literal paths for both keys and values in literalAnalyseExcludes. Then in some cases paths can be checked by just doing isset(literalAnalyseExcludes[path]) instead of looping over the whole thing and comparing one by one. But it's really diminishing returns (10% of 2% is 0.2%, so not really any observable difference), so I didn't bother to put it in the PR.