Add partial_sort_copy and adapt partial sort to c++ 20

[Jedi18]

Thanks to @fjtapia for his partial_sort_copy implementation.

Added tag_fallback_invoke overloads for parallel and container overloads, normal and range tests for partial_sort and partial_sort_copy.

Any background context you want to provide?
Issue #4822
Issue #3646
Issue #1668

[StellarBot]

Performance test report

HPX Performance

Comparison

BENCHMARK	NO-EXECUTOR
Future Overhead - Create Thread Hierarchical - Latch	++

Info

Property	Before	After
HPX Commit	254db57	b93c634
HPX Datetime	2021-08-21T11:38:52+00:00	2021-11-02T07:19:24+00:00
Datetime	2021-08-23T15:21:22.855927+02:00	2021-11-02T08:32:59.887174+01:00
Hostname	nid00446	nid01152
Envfile
Compiler	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0
Clustername	daint	daint

Comparison

BENCHMARK	FORK_JOIN_EXECUTOR_DEFAULT_FORK_JOIN_POLICY_ALLOCATOR	PARALLEL_EXECUTOR_DEFAULT_PARALLEL_POLICY_ALLOCATOR	SCHEDULER_EXECUTOR_DEFAULT_SCHEDULER_EXECUTOR_ALLOCATOR
Stream Benchmark - Add	(=)	(=)	-
Stream Benchmark - Scale	(=)	(=)	(=)
Stream Benchmark - Triad	-	(=)	-
Stream Benchmark - Copy	(=)	(=)	(=)

Info

Property	Before	After
HPX Commit	916f4d8	b93c634
HPX Datetime	2021-10-22T15:54:13+00:00	2021-11-02T07:19:24+00:00
Datetime	2021-10-25T11:52:24.316784+02:00	2021-11-02T08:33:15.228036+01:00
Hostname	nid01196	nid01152
Envfile
Compiler	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0
Clustername	daint	daint

Explanation of Symbols

Symbol	MEANING
=	No performance change (confidence interval within ±1%)
(=)	Probably no performance change (confidence interval within ±2%)
(+)/(-)	Very small performance improvement/degradation (≤1%)
+/-	Small performance improvement/degradation (≤5%)
++/--	Large performance improvement/degradation (≤10%)
+++/---	Very large performance improvement/degradation (>10%)
?	Probably no change, but quite large uncertainty (confidence interval with ±5%)
??	Unclear result, very large uncertainty (±10%)
???	Something unexpected…

[Jedi18]

@hkaiser Thanks for fixing the error!

[StellarBot]

Performance test report

HPX Performance

Comparison

BENCHMARK	NO-EXECUTOR
Future Overhead - Create Thread Hierarchical - Latch	(=)

Info

Property	Before	After
HPX Datetime	2021-08-21T11:38:52+00:00	2021-11-06T05:51:32+00:00
HPX Commit	254db57	15ccccb
Datetime	2021-08-23T15:21:22.855927+02:00	2021-11-06T07:07:26.652286+01:00
Envfile
Compiler	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0
Clustername	daint	daint
Hostname	nid00446	nid01540

Comparison

BENCHMARK	FORK_JOIN_EXECUTOR_DEFAULT_FORK_JOIN_POLICY_ALLOCATOR	PARALLEL_EXECUTOR_DEFAULT_PARALLEL_POLICY_ALLOCATOR	SCHEDULER_EXECUTOR_DEFAULT_SCHEDULER_EXECUTOR_ALLOCATOR
Stream Benchmark - Add	(=)	(=)	-
Stream Benchmark - Scale	(=)	(=)	(=)
Stream Benchmark - Triad	(=)	(=)	-
Stream Benchmark - Copy	(=)	(=)	(=)

Info

Property	Before	After
HPX Datetime	2021-10-22T15:54:13+00:00	2021-11-06T05:51:32+00:00
HPX Commit	916f4d8	15ccccb
Datetime	2021-10-25T11:52:24.316784+02:00	2021-11-06T07:07:41.969381+01:00
Envfile
Compiler	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0	/apps/daint/SSL/HPX/packages/llvm-11.0.0/bin/clang++ 11.0.0
Clustername	daint	daint
Hostname	nid01196	nid01540

Explanation of Symbols

Symbol	MEANING
=	No performance change (confidence interval within ±1%)
(=)	Probably no performance change (confidence interval within ±2%)
(+)/(-)	Very small performance improvement/degradation (≤1%)
+/-	Small performance improvement/degradation (≤5%)
++/--	Large performance improvement/degradation (≤10%)
+++/---	Very large performance improvement/degradation (>10%)
?	Probably no change, but quite large uncertainty (confidence interval with ±5%)
??	Unclear result, very large uncertainty (±10%)
???	Something unexpected…

[hkaiser]

LGTM, thanks!