Revert "Cray: Fix Cray compiler detection on new platforms"

The justification in commit 9ee4a428 (Cray: Fix Cray compiler
detection on new platforms, 2020-12-01, v3.19.2~26^2) confuses detection
of the CrayPrgEnv with identification of the Cray compiler.  The
change regressed detection of the CrayPrgEnv on non-Cray compilers.
Revert it pending further investigation into the original problem.

Fixes: #21894
31 jobs for !5889 with CrayPrgEnv-detection in 7 minutes and 36 seconds (queued for 2 seconds)
latest detached
Status Name Job ID Coverage
  Build
manual build:centos6-release #5590802
cmake build docker linux manual
passed build:debian10-iwyu #5590799
cmake build docker linux

00:02:31

manual build:fedora33-ninja #5590803
cmake build docker linux linux-3.17 manual
passed build:fedora33-sphinx #5590801
cmake build docker linux linux-3.17

00:07:36

passed build:fedora33-tidy #5590800
cmake build docker linux linux-3.17

00:05:36

manual build:macos-makefiles #5590805
cmake macos shell xcode-12.3 nonconcurrent manual
manual build:macos-ninja #5590804
cmake macos shell xcode-12.3 nonconcurrent manual
manual build:windows-vs2019-x64-ninja #5590806
cmake windows shell vs2019 msvc-19.28 nonconcurrent manual
 
  Test
created test:fedora33-ninja #5590807
cmake docker linux linux-3.17 x11
created test:macos-makefiles #5590809
cmake macos shell xcode-12.3 nonconcurrent
created test:macos-ninja #5590808
cmake macos shell xcode-12.3 nonconcurrent
created test:windows-vs2019-x64-ninja #5590810
cmake windows shell vs2019 msvc-19.28 nonconcurrent
 
  Test Ext
created test:cuda10.2-nvidia #5590813
cmake cuda-rt docker linux
created test:debian10-ninja #5590811
cmake build docker linux linux-3.17
created test:fedora33-makefiles #5590812
cmake build docker linux linux-3.17
created test:fedora33-ninja-multi #5590814
cmake build docker linux linux-3.17
created test:macos-xcode #5590815
cmake macos shell xcode-12.3 concurrent
created test:windows-vs2019-x64 #5590816
cmake windows shell vs2019 msvc-19.28 concurrent
 
  External
passed cdash

passed ghostflow-check-master

passed ghostflow-check-release

passed ghostflow-stager

passed cdash

passed cdash

passed cdash

passed cdash

passed cdash

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager