Update MIR opt tests with new name

Author: ecstatic-morse

src/test/mir-opt/const_prop/switch_int.main.SimplifyBranches-after-const-prop.diff renamed to src/test/mir-opt/const_prop/switch_int.main.SimplifyConstCondition-after-const-prop.diff

@@ -1,5 +1,5 @@
-- // MIR for `main` before SimplifyBranches-after-const-prop
-+ // MIR for `main` after SimplifyBranches-after-const-prop
+- // MIR for `main` before SimplifyConstCondition-after-const-prop
++ // MIR for `main` after SimplifyConstCondition-after-const-prop
 
   fn main() -> () {
       let mut _0: ();                      // return place in scope 0 at $DIR/switch_int.rs:6:11: 6:11

src/test/mir-opt/const_prop/switch_int.rs

@@ -2,7 +2,7 @@
 fn foo(_: i32) { }
 
 // EMIT_MIR switch_int.main.ConstProp.diff
-// EMIT_MIR switch_int.main.SimplifyBranches-after-const-prop.diff
+// EMIT_MIR switch_int.main.SimplifyConstCondition-after-const-prop.diff
 fn main() {
     match 1 {
         1 => foo(0),

src/test/mir-opt/early_otherwise_branch_68867.rs

@@ -11,7 +11,7 @@ pub enum ViewportPercentageLength {
 }
 
 // EMIT_MIR early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.diff
-// EMIT_MIR early_otherwise_branch_68867.try_sum EarlyOtherwiseBranch.before SimplifyBranches-final.after
+// EMIT_MIR early_otherwise_branch_68867.try_sum EarlyOtherwiseBranch.before SimplifyConstCondition-final.after
 #[no_mangle]
 pub extern "C" fn try_sum(
     x: &ViewportPercentageLength,

src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.before-SimplifyBranches-final.after.diff renamed to src/test/mir-opt/early_otherwise_branch_68867.try_sum.EarlyOtherwiseBranch.before-SimplifyConstCondition-final.after.diff

@@ -1,5 +1,5 @@
 - // MIR for `try_sum` before EarlyOtherwiseBranch
-+ // MIR for `try_sum` after SimplifyBranches-final
++ // MIR for `try_sum` after SimplifyConstCondition-final
 
   fn try_sum(_1: &ViewportPercentageLength, _2: &ViewportPercentageLength) -> Result<ViewportPercentageLength, ()> {
       debug x => _1;                       // in scope 0 at $DIR/early_otherwise_branch_68867.rs:17:5: 17:6

src/test/mir-opt/simplify_if.main.SimplifyBranches-after-const-prop.diff renamed to src/test/mir-opt/simplify_if.main.SimplifyConstCondition-after-const-prop.diff

@@ -1,5 +1,5 @@
-- // MIR for `main` before SimplifyBranches-after-const-prop
-+ // MIR for `main` after SimplifyBranches-after-const-prop
+- // MIR for `main` before SimplifyConstCondition-after-const-prop
++ // MIR for `main` after SimplifyConstCondition-after-const-prop
 
   fn main() -> () {
       let mut _0: ();                      // return place in scope 0 at $DIR/simplify_if.rs:5:11: 5:11

src/test/mir-opt/simplify_if.rs

@@ -1,7 +1,7 @@
 #[inline(never)]
 fn noop() {}
 
-// EMIT_MIR simplify_if.main.SimplifyBranches-after-const-prop.diff
+// EMIT_MIR simplify_if.main.SimplifyConstCondition-after-const-prop.diff
 fn main() {
     if false {
         noop();