Remove non-transparent requirement added to prerelease gems

I think we can safely assume these days that all RubyGems and Bundler
versions that will ever bundle a new gem created in 2023 support
prereleases.

So this non transparent requirement is not necessary.

In my opinion, it should be the gem author to explicitly add this
constraint, not RubyGems.

lib/rubygems/specification.rb

@@ -2674,19 +2674,12 @@ def validate_permissions
   rubygems_deprecate :validate_permissions
 
   ##
-  # Set the version to +version+, potentially also setting
-  # required_rubygems_version if +version+ indicates it is a
-  # prerelease.
+  # Set the version to +version+.
 
   def version=(version)
     @version = Gem::Version.create(version)
     return if @version.nil?
 
-    # skip to set required_ruby_version when pre-released rubygems.
-    # It caused to raise CircularDependencyError
-    if @version.prerelease? && (@name.nil? || @name.strip != "rubygems")
-      self.required_rubygems_version = "> 1.3.1"
-    end
     invalidate_memoized_attributes
   end
 

test/rubygems/test_gem_specification.rb

@@ -2005,12 +2005,6 @@ def test_platform_equals_legacy
     assert_equal Gem::Platform.new("ppc-darwin"), @a1.platform
   end
 
-  def test_prerelease_spec_adds_required_rubygems_version
-    @prerelease = util_spec("tardis", "2.2.0.a")
-    refute @prerelease.required_rubygems_version.satisfied_by?(Gem::Version.new("1.3.1"))
-    assert @prerelease.required_rubygems_version.satisfied_by?(Gem::Version.new("1.4.0"))
-  end
-
   def test_require_paths
     enable_shared "no" do
       ext_spec