run full query stack print just when RUST_BACKTRACE is set

Author: hosseind75

compiler/rustc_middle/src/ty/query/plumbing.rs

@@ -124,7 +124,11 @@ impl<'tcx> TyCtxt<'tcx> {
         })
     }
 
-    pub fn try_print_query_stack(handler: &Handler, num_frames: Option<usize>) {
+    pub fn try_print_query_stack(
+        handler: &Handler,
+        num_frames: Option<usize>,
+        backtrace: Option<bool>,
+    ) {
         eprintln!("query stack during panic:");
 
         // Be careful reyling on global state here: this code is called from