Remove binary data at installation

And revert "Relaxed warning assertions",
6f9be8505d.

test/rubygems/test_require.rb

@@ -509,11 +509,11 @@ class TestGemRequire < Gem::TestCase
         _, err = capture_subprocess_io do
           system(@@ruby, "-w", "-rpp", "--disable=gems", "-I", lib, "-C", dir, "-I.", "main.rb")
         end
-        assert_includes err, "main.rb:1: warning: uplevel\ntest\n"
+        assert_equal "main.rb:1: warning: uplevel\ntest\n", err
         _, err = capture_subprocess_io do
           system(@@ruby, "-w", "-rpp", "--enable=gems", "-I", lib, "-C", dir, "-I.", "main.rb")
         end
-        assert_includes err, "main.rb:1: warning: uplevel\ntest\n"
+        assert_equal "main.rb:1: warning: uplevel\ntest\n", err
       end
     end
 
@@ -524,11 +524,11 @@ class TestGemRequire < Gem::TestCase
         _, err = capture_subprocess_io do
           system(@@ruby, "-w", "-rpp", "--disable=gems", "-I", lib, "-C", dir, "-I.", "main.rb")
         end
-        assert_includes err, "{:x=>1}\n{:y=>2}\n"
+        assert_equal "{:x=>1}\n{:y=>2}\n", err
         _, err = capture_subprocess_io do
           system(@@ruby, "-w", "-rpp", "--enable=gems", "-I", lib, "-C", dir, "-I.", "main.rb")
         end
-        assert_includes err, "{:x=>1}\n{:y=>2}\n"
+        assert_equal "{:x=>1}\n{:y=>2}\n", err
       end
     end
   end

tool/rbinstall.rb

@@ -838,7 +838,7 @@ def install_default_gem(dir, srcdir)
     puts "#{INDENT}#{gemspec.name} #{gemspec.version}"
     gemspec_path = File.join(default_spec_dir, "#{full_name}.gemspec")
     open_for_install(gemspec_path, $data_mode) do
-      gemspec.to_ruby
+      gemspec.to_ruby.gsub(/.*\0.*\n/, '')
     end
 
     specific_gem_dir = File.join(gem_dir, 'gems', full_name)