Mingw: Exclude failing tests due to the crt change

Mingw crt-git 12.0.0.r369.g0d4221712-1 now prohibits "command line
contains characters that are not supported in the active code page".
https://sourceforge.net/p/mingw-w64/mingw-w64/ci/0d42217123d3aec0341b79f6d959c76e09648a1e/

Provisionally exclude tests that fail by passing such characters.

Author: nobu

test/.excludes/TestArgf.rb

@@ -0,0 +1,9 @@
+if RUBY_PLATFORM.include?("mingw")
+  reason = <<~EOS
+  Mingw crt-git 12.0.0.r369.g0d4221712-1 now prohibits "command line
+  contains characters that are not supported in the active code page".
+  https://sourceforge.net/p/mingw-w64/mingw-w64/ci/0d42217123d3aec0341b79f6d959c76e09648a1e/
+  EOS
+
+  exclude(:test_inplace_nonascii, reason)
+end

test/.excludes/TestRubyOptions.rb

@@ -0,0 +1,11 @@
+if RUBY_PLATFORM.include?("mingw")
+  reason = <<~EOS
+  Mingw crt-git 12.0.0.r369.g0d4221712-1 now prohibits "command line
+  contains characters that are not supported in the active code page".
+  https://sourceforge.net/p/mingw-w64/mingw-w64/ci/0d42217123d3aec0341b79f6d959c76e09648a1e/
+  EOS
+
+  exclude(:test_chdir, reason)
+  exclude(:test_locale_codepage, reason)
+  exclude(:test_command_line_progname_nonascii, reason)
+end