[Chapel Merge] Deprecate sockets provider

Branch: refs/heads/main
Revision: 974fd71
Author: jhh67
Log Message:

Merge pull request #18300 from jhh67/T2459

Deprecate sockets provider

The sockets provider has been deprecated by libfabric. Only choose sockets if it is specified via the FI_PROVIDER environment variable, and print a warning message if it is chosen.

[Reviewed by @gbtitus].

Modified Files:
M runtime/src/comm/ofi/comm-ofi.c

Compare: https://github.com/chapel-lang/chapel/compare/8b4e03417143...974fd7130a30