Support expressions in selectattr/rejectattr again, more efficiently v2

[mattcoley]

Take 2. I will fix this up.

[samukce]

There is an unused method parameter in this method. Should we remove it? Map<String, Object> kwargs

[samukce]

The String.format has some performance issues. So, for curiosity, I ran a benchmark to compare the approaches.

Those are the results:

Benchmark                                                Mode  Cnt   Score   Error  Units
StringConcatSimulation.concatWithConcatFunction            ss   25   1.900 ± 0.120  ms/op
StringConcatSimulation.concatWithPlus                      ss   25   2.079 ± 0.438  ms/op
StringConcatSimulation.concatWithStringBuilder             ss   25   1.871 ± 0.436  ms/op
StringConcatSimulation.concatWithStringBuilderWithCount    ss   25   1.720 ± 0.255  ms/op
StringConcatSimulation.concatWithStringFormat              ss   25  15.145 ± 2.836  ms/op

I would suggest using StringBuilder instead.

Suggested change

	return String.format("%s.%s", tempValue, expression).trim();
	return new StringBuilder()
	.append(tempValue)
	.append(".")
	.append(expression)
	.toString()
	.trim();