Be more tolerant in File.mtime spec

Author: eregon

spec/ruby/core/file/mtime_spec.rb

@@ -12,7 +12,7 @@
 
   it "returns the modification Time of the file" do
     File.mtime(@filename).should be_kind_of(Time)
-    File.mtime(@filename).should be_close(@mtime, 2.0)
+    File.mtime(@filename).should be_close(@mtime, 60.0)
   end
 
   guard -> { platform_is :linux or (platform_is :windows and ruby_version_is '2.5') } do