Bug 1758780 - Use the same version of clang as for other builds for sm fuzzing builds. r=firefox-build-system-reviewers,mhentges

It used to be this way, until bug 1731582 made it tied to clang-12 to
keep it to that version. This was subsequently upgraded to clang-13 in
bug 1736459, but this should really have been changed back to
unversioned clang.

Differential Revision: https://phabricator.services.mozilla.com/D143134

taskcluster/ci/spidermonkey/linux.yml

@@ -431,7 +431,7 @@ sm-fuzzing-linux64/opt:
         spidermonkey-variant: fuzzing
     fetches:
         toolchain:
-            - linux64-clang-13
+            - linux64-clang
             - linux64-rust
             - linux64-cbindgen
             - linux64-dump_syms