[Chapel Merge] Improve time-to-completion estimation better in ar

Branch: refs/heads/main
Revision: d67222e
Author: gbtitus
Log Message:

Merge pull request #18371 from gbtitus/arrXfer-nops-chex

Improve time-to-completion estimation better in arrayTransfer test.

(Not reviewed; minor, test only, and discussed long ago with @ronawho.)

The arrayTransfer test inherited poor time-to-completion estimation
logic from the many-to-one test. The latter was fixed in #17676. Here,
fix the former similarly. I added some temporary instrumentation and
depending on circumstances saw as many as 100x fewer completion checks
in the course of a run.

Modified Files:
M test/performance/comm/low-level/arrayTransfer.chpl

Compare: https://github.com/chapel-lang/chapel/compare/25afb9f8ee03...d67222e0cfc9