Support using unversioned lld as linker too (#8189)

* Support using unversioend lld as linker too

On Fedora and RHEL the `lld` executable is the plain unversioned `lld`.
That's also usable as a linker if it's recent enough.

See dotnet/runtime#58959 (comment)
for more details and discussion.

* Query clang's -fuse-ld to decide whether lld is okay to use

Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>

Co-authored-by: Adeel Mujahid <3840695+am11@users.noreply.github.com>

eng/common/native/init-compiler.sh

@@ -112,7 +112,7 @@ if [[ -z "$CC" ]]; then
 fi
 
 if [[ "$compiler" == "clang" ]]; then
-    if command -v "lld$desired_version" > /dev/null; then
+    if "$CC" -fuse-ld=lld -Wl,--version 2>&1; then
         # Only lld version >= 9 can be considered stable
         if [[ "$majorVersion" -ge 9 ]]; then
             LDFLAGS="-fuse-ld=lld"