Improve Binder performance slightly

[dreis2211]

Hi,

I'm currently trying to improve the startup of a medium sized app and found a couple of minor optimization opportunities in the Binder logic:

1. Skip looking for descendants if context.depth is 0. (Was there before, but only as a subsequent condition)
2. Defer overhead of getting ConfigurationPropertys in IndexedElementsBinder:: getKnownIndexedChildren until it's needed. The idea is that this is only really necessary if there are unbound properties - which should be the exception rather than the norm.

Applying this patch shows me the following results for the initializr benchmarks we used in the past already:

2.3.0.M3
Benchmark                        (prof)   Mode  Cnt      Score      Error  Units
PropertiesBenchmarkIT.auto       medium  thrpt   10    238,644 ±  138,881  ops/s
PropertiesBenchmarkIT.auto:size  medium  thrpt   10   1340,000                 #
PropertiesBenchmarkIT.auto        small  thrpt   10  16863,321 ± 8881,464  ops/s
PropertiesBenchmarkIT.auto:size   small  thrpt   10     10,000                 #
PropertiesBenchmarkIT.auto        large  thrpt   10      4,492 ±    0,647  ops/s
PropertiesBenchmarkIT.auto:size   large  thrpt   10  10930,000                 #

Patch
Benchmark                        (prof)   Mode  Cnt      Score      Error  Units
PropertiesBenchmarkIT.auto       medium  thrpt   10    275,289 ±  144,481  ops/s
PropertiesBenchmarkIT.auto:size  medium  thrpt   10   1340,000                 #
PropertiesBenchmarkIT.auto        small  thrpt   10  20426,557 ± 4507,749  ops/s
PropertiesBenchmarkIT.auto:size   small  thrpt   10     10,000                 #
PropertiesBenchmarkIT.auto        large  thrpt   10      5,121 ±    0,428  ops/s
PropertiesBenchmarkIT.auto:size   large  thrpt   10  10930,000                 #

I also ran 2.3.0.M3 vs. this patch against the config example which we used in the past to optimize the binding of large properties:

	2.3.0.M3	Patch
	4.986	4.790
	4.715	4.682
	4.833	4.651
	4.719	4.762
	5.161	4.743
	4.830	4.744
	5.081	4.791
	5.850	4.715
	4.767	4.803
	4.877	4.804
Mean	4.982	4.749
Range	1.135	0.153

I should note that I see relatively volatile timings on my local machine, but always in favor of the new patched version. Nonetheless, I'd give it a try before merging this if I were you - even if the improvements seem relatively straight-forward ;-)

Let me know what you think.
Cheers,
Christoph

[dreis2211]

Test failure seems unrelated.

[wilkinsona]

Test failure seems unrelated

It looks like another occurrence of #20790. Hopefully we won't see that one any more 🤞.