Use EnvUtil.with_default_external in tests needing it

* Reverts part of r54522.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61193 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_numeric.rb

@@ -22,10 +22,12 @@ class TestNumeric < Test::Unit::TestCase
     assert_raise_with_message(TypeError, /:\u{3042}/) {1&:"\u{3042}"}
     assert_raise_with_message(TypeError, /:\u{3042}/) {1|:"\u{3042}"}
     assert_raise_with_message(TypeError, /:\u{3042}/) {1^:"\u{3042}"}
+    EnvUtil.with_default_external(Encoding::US_ASCII) do
       assert_raise_with_message(TypeError, /:"\\u3042"/) {1+:"\u{3042}"}
       assert_raise_with_message(TypeError, /:"\\u3042"/) {1&:"\u{3042}"}
       assert_raise_with_message(TypeError, /:"\\u3042"/) {1|:"\u{3042}"}
       assert_raise_with_message(TypeError, /:"\\u3042"/) {1^:"\u{3042}"}
+    end
 
     bug10711 = '[ruby-core:67405] [Bug #10711]'
     exp = "1.2 can't be coerced into Integer"

test/ruby/test_regexp.rb

@@ -667,7 +667,11 @@ class TestRegexp < Test::Unit::TestCase
     key = "\u{3042}"
     [Encoding::UTF_8, Encoding::Shift_JIS, Encoding::EUC_JP].each do |enc|
       idx = key.encode(enc)
-      test.call {|m| assert_raise_with_message(IndexError, /#{idx}/, bug10877) {m[idx]} }
+      test.call {|m|
+        EnvUtil.with_default_external(enc) do
+          assert_raise_with_message(IndexError, /#{idx}/, bug10877) {m[idx]}
+        end
+      }
     end
     test.call {|m| assert_equal(/a/, m.regexp) }
     test.call {|m| assert_equal("abc", m.string) }