Never run cargo check on the rustc source

Author: DJMcNab

crates/project_model/src/workspace.rs

@@ -276,11 +276,8 @@ impl ProjectWorkspace {
 
     pub fn collect_build_data_configs(&self, collector: &mut BuildDataCollector) {
         match self {
-            ProjectWorkspace::Cargo { cargo, rustc, .. } => {
+            ProjectWorkspace::Cargo { cargo, .. } => {
                 collector.add_config(&cargo.workspace_root(), cargo.build_data_config().clone());
-                if let Some(rustc) = rustc {
-                    collector.add_config(rustc.workspace_root(), rustc.build_data_config().clone());
-                }
             }
             _ => {}
         }