Rollup merge of #144614 - cjgillot:fortify-unneeded, r=scottmcm

Fortify RemoveUnneededDrops test.

Test tweak that is useful in preparation for #144561

Author: samueltardieu

tests/mir-opt/remove_unneeded_drops.cannot_opt_generic.RemoveUnneededDrops.diff

@@ -0,0 +1,15 @@
+- // MIR for `cannot_opt_generic` before RemoveUnneededDrops
++ // MIR for `cannot_opt_generic` after RemoveUnneededDrops
+  
+  fn cannot_opt_generic(_1: T) -> () {
+      let mut _0: ();
+  
+      bb0: {
+          drop(_1) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          return;
+      }
+  }
+  

tests/mir-opt/remove_unneeded_drops.cannot_opt_generic.RemoveUnneededDrops.panic-abort.diff

@@ -0,0 +1,15 @@
+- // MIR for `dont_opt` before RemoveUnneededDrops
++ // MIR for `dont_opt` after RemoveUnneededDrops
+  
+  fn dont_opt(_1: Vec<bool>) -> () {
+      let mut _0: ();
+  
+      bb0: {
+          drop(_1) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          return;
+      }
+  }
+  

tests/mir-opt/remove_unneeded_drops.cannot_opt_generic.RemoveUnneededDrops.panic-unwind.diff

@@ -0,0 +1,15 @@
+- // MIR for `opt` before RemoveUnneededDrops
++ // MIR for `opt` after RemoveUnneededDrops
+  
+  fn opt(_1: bool) -> () {
+      let mut _0: ();
+  
+      bb0: {
+-         drop(_1) -> [return: bb1, unwind unreachable];
+-     }
+- 
+-     bb1: {
+          return;
+      }
+  }
+  

tests/mir-opt/remove_unneeded_drops.dont_opt.RemoveUnneededDrops.diff

@@ -0,0 +1,15 @@
+- // MIR for `opt_generic_copy` before RemoveUnneededDrops
++ // MIR for `opt_generic_copy` after RemoveUnneededDrops
+  
+  fn opt_generic_copy(_1: T) -> () {
+      let mut _0: ();
+  
+      bb0: {
+-         drop(_1) -> [return: bb1, unwind unreachable];
+-     }
+- 
+-     bb1: {
+          return;
+      }
+  }
+