Unbreak fuzzing build when span-locations is used

    error[E0432]: unresolved import `crate::imp::invalidate_current_thread_spans`
       --> src/lib.rs:176:9
        |
    176 | pub use crate::imp::invalidate_current_thread_spans;
        |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no `invalidate_current_thread_spans` in `fallback`
        |
    note: found an item that was configured out
       --> src/fallback.rs:338:8
        |
    338 | pub fn invalidate_current_thread_spans() {
        |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Author: dtolnay

src/fallback.rs

@@ -334,8 +334,9 @@ thread_local! {
     });
 }
 
-#[cfg(all(span_locations, not(fuzzing)))]
+#[cfg(span_locations)]
 pub fn invalidate_current_thread_spans() {
+    #[cfg(not(fuzzing))]
     SOURCE_MAP.with(|sm| sm.borrow_mut().files.truncate(1));
 }