Move version guard in fiber storage spec to top level

This feature is introduced in Ruby 3.2, so by wrapping everything in the
version guard there is no more need to repeat in at every block.

core/fiber/storage_spec.rb

@@ -1,7 +1,7 @@
 require_relative '../../spec_helper'
 
-describe "Fiber.new(storage:)" do
-  ruby_version_is "3.2" do
+ruby_version_is "3.2" do
+  describe "Fiber.new(storage:)" do
     it "creates a Fiber with the given storage" do
       storage = {life: 42}
       fiber = Fiber.new(storage: storage) { Fiber.current.storage }
@@ -31,21 +31,17 @@
       -> { Fiber.new(storage: {life: 43, Object.new => 44}) {} }.should raise_error(TypeError)
     end
   end
-end
 
-describe "Fiber#storage" do
-  ruby_version_is "3.2" do
+  describe "Fiber#storage" do
     it "cannot be accessed from a different fiber" do
       f = Fiber.new(storage: {life: 42}) { nil }
       -> {
         f.storage
       }.should raise_error(ArgumentError, /Fiber storage can only be accessed from the Fiber it belongs to/)
     end
   end
-end
 
-describe "Fiber#storage=" do
-  ruby_version_is "3.2" do
+  describe "Fiber#storage=" do
     it "can clear the storage of the fiber" do
       fiber = Fiber.new(storage: {life: 42}) do
         Fiber.current.storage = nil
@@ -75,10 +71,8 @@
       -> { Fiber.current.storage = {life: 43, Object.new => 44} }.should raise_error(TypeError)
     end
   end
-end
 
-describe "Fiber.[]" do
-  ruby_version_is "3.2" do
+  describe "Fiber.[]" do
     it "returns the value of the given key in the storage of the current fiber" do
       Fiber.new(storage: {life: 42}) { Fiber[:life] }.resume.should == 42
     end
@@ -102,10 +96,8 @@
       -> { Fiber[Object.new] }.should raise_error(TypeError)
     end
   end
-end
 
-describe "Fiber.[]=" do
-  ruby_version_is "3.2" do
+  describe "Fiber.[]=" do
     it "sets the value of the given key in the storage of the current fiber" do
       Fiber.new(storage: {life: 42}) { Fiber[:life] = 43; Fiber[:life] }.resume.should == 43
     end
@@ -137,10 +129,8 @@
       Fiber.new(storage: {life: 42}) { Fiber[:life] = nil; Fiber.current.storage }.resume.should == {}
     end
   end
-end
 
-describe "Thread.new" do
-  ruby_version_is "3.2" do
+  describe "Thread.new" do
     it "creates a thread with the storage of the current fiber" do
       fiber = Fiber.new(storage: {life: 42}) do
         Thread.new { Fiber.current.storage }.value