Use `MirPatch` in `EnumSizeOpt`.

Instead of `expand_statements`. This makes the code shorter and
consistent with other MIR transform passes.

The tests require updating because there is a slight change in
MIR output:
- the old code replaced the original statement with twelve new
  statements.
- the new code inserts converts the original statement to a `nop` and
  then insert twelve new statements in front of it.

I.e. we now end up with an extra `nop`, which doesn't matter at all.

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff b/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff
index 6d1e2a72fdb..96c5aadd85f 100644
--- a/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff
+++ b/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff
@@ -47,6 +47,7 @@
 +         Deinit(_8);
 +         copy_nonoverlapping(dst = copy _9, src = copy _11, count = copy _7);
 +         StorageDead(_4);
++         nop;
           StorageDead(_2);
 -         _0 = move _1;
 +         StorageLive(_12);
@@ -61,6 +62,7 @@
 +         Deinit(_16);
 +         copy_nonoverlapping(dst = copy _17, src = copy _19, count = copy _15);
 +         StorageDead(_12);
++         nop;
           StorageDead(_1);
           return;
       }