Change perl -v version format

Change perl -v version format

New format:

  This is perl 5, version 11, subversion 1 (v5.11.1) ...

The rationale for this change is that the Perl 5 interpreter will never
increment PERL_REVISION from 5 to 6, so we want people to start focusing
on the PERL_VERSION number as most significant and PERL_SUBVERSION as
equivalent to a "release number".  In other words, "perl 5" is a
language, this is the 11th version of it, and the second release of that
version (counting from zero).  Among other things, this makes the
output of -v and -V more consistent.

The old v-string style is included for familiarity and usage in code.
For builds from git, it will include the same extended format as it
did before, e.g. "(v5.11.1-176-gaf24cc9*)"