Cray support: use linux platform for newer craype versions (#29392)

Newer versions of the CrayPE for EX systems have standalone compiler executables for CCE and compiler wrappers for Cray MPICH. With those, we can treat the cray systems as part of the linux platform rather than having a separate cray platform.

This PR:
- [x] Changes cray platform detection to ignore EX systems with Craype version 21.10 or later
- [x] Changes the cce compiler to be detectable via paths
- [x] Changes the spack compiler wrapper to understand the executable names for the standalone cce compiler (`craycc`, `crayCC`, `crayftn`).

lib/spack/env/cc

@@ -241,28 +241,28 @@ case "$command" in
         mode=cpp
         debug_flags="-g"
         ;;
-    cc|c89|c99|gcc|clang|armclang|icc|icx|pgcc|nvc|xlc|xlc_r|fcc|amdclang|cl.exe)
+    cc|c89|c99|gcc|clang|armclang|icc|icx|pgcc|nvc|xlc|xlc_r|fcc|amdclang|cl.exe|craycc)
         command="$SPACK_CC"
         language="C"
         comp="CC"
         lang_flags=C
         debug_flags="-g"
         ;;
-    c++|CC|g++|clang++|armclang++|icpc|icpx|dpcpp|pgc++|nvc++|xlc++|xlc++_r|FCC|amdclang++)
+    c++|CC|g++|clang++|armclang++|icpc|icpx|dpcpp|pgc++|nvc++|xlc++|xlc++_r|FCC|amdclang++|crayCC)
         command="$SPACK_CXX"
         language="C++"
         comp="CXX"
         lang_flags=CXX
         debug_flags="-g"
         ;;
-    ftn|f90|fc|f95|gfortran|flang|armflang|ifort|ifx|pgfortran|nvfortran|xlf90|xlf90_r|nagfor|frt|amdflang)
+    ftn|f90|fc|f95|gfortran|flang|armflang|ifort|ifx|pgfortran|nvfortran|xlf90|xlf90_r|nagfor|frt|amdflang|crayftn)
         command="$SPACK_FC"
         language="Fortran 90"
         comp="FC"
         lang_flags=F
         debug_flags="-g"
         ;;
-    f77|xlf|xlf_r|pgf77|amdflang)
+    f77|xlf|xlf_r|pgf77)
         command="$SPACK_F77"
         language="Fortran 77"
         comp="F77"

lib/spack/env/cce/case-insensitive/crayCC

@@ -0,0 +1 @@
+../../cc

lib/spack/env/cce/craycc

@@ -0,0 +1 @@
+../cc

lib/spack/env/cce/crayftn

@@ -0,0 +1 @@
+../cc