Revert "compare with llvm-18"

This reverts commit 3df2e19.

Author: vszakats

_ci-linux-debian.sh

@@ -14,7 +14,7 @@ extra=''
 dl=''
 
 if [[ "${CW_CONFIG:-}" != *'gcc'* ]]; then
-  [ -n "${CW_CCSUFFIX:-}" ] || export CW_CCSUFFIX='-18'
+  [ -n "${CW_CCSUFFIX:-}" ] || export CW_CCSUFFIX='-19'
   extra+=" llvm${CW_CCSUFFIX} clang${CW_CCSUFFIX} lld${CW_CCSUFFIX}"
 fi