Update to 9999.27

Upstream changes:
9999.27    2019-04-05
    - Update the documentation on the atomic write. We no longer use the pid
      and I neglected to update the documentation as such. (RT #129029)
    - Localize $^W to stop File::Temp from warning the user when the -w flag
      is on while we're grabbing a temporary file name. (RT #129029)

9999.26    2019-02-13
    - Reduce the size of handle.t to prevent failures on systems with limits set
    - Skip all tests in the suite that relied on overriding syswrite to test
      failure mechanisms as CORE::print cannot be overridden.
    - Refactor write_file to use print rather than syswrite.
      - When performing an atomic write, make sure we find a good temporary file
        so that we don't accidentally overwrite a file that may already exist in
        the working directory.
      - Stop re-working the line endings on write_file when on Windows as the use
        of print now allows layers to provide that functionality.
    - Add File::Basename, File::Spec, File::Temp, and IO::Handle to the runtime
      prereqs. These were already testing prereqs and are core.
    - Perl 5.30 compliance is complete at this point.

(wen)