stop having 'static in dump-mir names

src/librustc_mir/transform/simplify_branches.rs

@@ -60,4 +60,7 @@ impl<'l> Pass for SimplifyBranches<'l> {
     fn disambiguator<'a>(&'a self) -> Option<Box<fmt::Display+'a>> {
         Some(Box::new(self.label))
     }
+
+    // avoid calling `type_name` - it contains `<'static>`
+    fn name(&self) -> &str { "SimplifyBranches" }
 }

src/librustc_mir/transform/simplify_cfg.rs

@@ -62,6 +62,9 @@ impl<'l> Pass for SimplifyCfg<'l> {
     fn disambiguator<'a>(&'a self) -> Option<Box<fmt::Display+'a>> {
         Some(Box::new(self.label))
     }
+
+    // avoid calling `type_name` - it contains `<'static>`
+    fn name(&self) -> &str { "SimplifyCfg" }
 }
 
 pub struct CfgSimplifier<'a, 'tcx: 'a> {