Disable resolving hostnames if TCP is disabled

[hkaiser]

Fixes #6388

@JiakunYan would you be able to check whether this resolves the issue you reported?

[codacy-production]

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Coverage variation	Diff coverage
-0.01%	36.36%

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (31a8a03)	189436	161286	85.14%
Head commit (b9ba56a)	189031 (-405)	160926 (-360)	85.13% (-0.01%)

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Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#6389)	22	8	36.36%

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[JiakunYan]

Is it possible to also disable these (

hpx/libs/full/command_line_handling/src/command_line_handling.cpp

Line 728 in d165ef8

hpx_host = mapnames.map(hpx_host, hpx_port);

and

hpx/libs/full/command_line_handling/src/command_line_handling.cpp

Line 729 in d165ef8

agas_host = mapnames.map(agas_host, agas_port);

)? The map function will also call resolve_hostname.

[hkaiser]

Is it possible to also disable these (

hpx/libs/full/command_line_handling/src/command_line_handling.cpp

Line 728 in d165ef8

hpx_host = mapnames.map(hpx_host, hpx_port);

and

hpx/libs/full/command_line_handling/src/command_line_handling.cpp

Line 729 in d165ef8

agas_host = mapnames.map(agas_host, agas_port);

)? The map function will also call resolve_hostname.

Done. Thanks!

[JiakunYan]

Should work now! I only tested it on 2 nodes. I need to let the Expanse support team test the program on 128 nodes to see whether it really fixes things or not, but I think we can merge it now.