test/ruby/test_process (test_no_curdir): tentatively skipped on Solaris

The test gets stuck on Solaris CI.

http://rubyci.s3.amazonaws.com/solaris11-gcc/ruby-master/log/20211006T050007Z.fail.html.gz#test-all
```
[14558/21042] TestProcess#test_no_curdirtimeout: output interval exceeds 1800.0 seconds.
timeout: the process group 3857 is alive.
```

Related to ee89543e09

test/ruby/test_process.rb

@@ -1732,6 +1732,9 @@ class TestProcess < Test::Unit::TestCase
   end
 
   def test_no_curdir
+    if /solaris/i =~ RUBY_PLATFORM
+      skip "Temporary skip to avoid CI failures after commit to use realpath on required files"
+    end
     with_tmpchdir {|d|
       Dir.mkdir("vd")
       status = nil