[mono] Don't use lld on s390x architecture (#78032)

It doesn't work there. Fixes #78026

Author: akoeplinger

eng/common/native/init-compiler.sh

@@ -132,8 +132,8 @@ if [[ -z "$CC" ]]; then
     exit 1
 fi
 
-# Only lld version >= 9 can be considered stable
-if [[ "$compiler" == "clang" && "$majorVersion" -ge 9 ]]; then
+# Only lld version >= 9 can be considered stable. lld doesn't support s390x.
+if [[ "$compiler" == "clang" && "$majorVersion" -ge 9 && "$build_arch" != "s390x" ]]; then
     if "$CC" -fuse-ld=lld -Wl,--version >/dev/null 2>&1; then
         LDFLAGS="-fuse-ld=lld"
     fi