It loads `ext/fiddle/lib/fiddle/version.rb`, which causes constant
redefinition warning:
20200523T153003Z.log.html.gz
```
[ 6317/20193] TestDefaultGems#test_validate_gemspec/home/chkbuild/chkbuild/tmp/build/20200523T153003Z/ruby/ext/fiddle/lib/fiddle/version.rb:2: warning: already initialized constant Fiddle::VERSION
/home/chkbuild/chkbuild/tmp/build/20200523T153003Z/ruby/.ext/common/fiddle/version.rb:2: warning: previous definition of VERSION was here
= 0.16 s
```
This changeset read the version by manual parsing hack which is also
used in stringio and zlib.