Revert the related commits about `Tempfile.open` change.

  Start with https://github.com/ruby/ruby/commit/fa21985a7a2f8f52a8bd82bd12a724e9dca74934
  to https://github.com/ruby/ruby/commit/d7492a0be885ea9f2b9f71e3e95582f9a859c439

1 files changed, 8 insertions, 0 deletions

diff --git a/tool/lib/minitest/unit.rb b/tool/lib/minitest/unit.rb
index 9066782322..c325134e63 100644
--- a/tool/lib/minitest/unit.rb
+++ b/tool/lib/minitest/unit.rb
@@ -122,11 +122,16 @@ module MiniTest
       return "Expected: #{mu_pp exp}\n  Actual: #{mu_pp act}" unless
         need_to_diff
 
+      tempfile_a = nil
+      tempfile_b = nil
+
       Tempfile.open("expect") do |a|
+        tempfile_a = a
         a.puts expect
         a.flush
 
         Tempfile.open("butwas") do |b|
+          tempfile_b = b
           b.puts butwas
           b.flush
 
@@ -147,6 +152,9 @@ module MiniTest
       end
 
       result
+    ensure
+      tempfile_a.close! if tempfile_a
+      tempfile_b.close! if tempfile_b
     end
 
     ##