Revert "Add support for test.valgrind parallel testing"

This reverts commit f0aff2daa44923f600f6e1f2429a2add2214a9d5
"Add support for test.valgrind parallel testing"

This patch was accidentally pushed (by me); it breaks some things.  We
will wait to add this support until after 5.20
perlrebackslash, perlreref.pod: White space only

Fit verbatim lines into 79 columns
fix killpg on Win32, to meet posix expectations for killpg

On Win32 Perls built without PERL_IMPLICIT_SYS, killpg from win32.c was
directly called by Perl_apply, yet killpg's return value had Win32
behavior, not POSIX behavior. Modify killpg token to have same meaning as
PerlProcKillpg/PerlProc_killpg has on PERL_IMPLICIT_SYS builds. Use a
macro rather than create a win32_killpg C function since win32_killpg would
be nothing but a call to win32_kill anyways. win32_kill contains the Win32
to POSIX semantics conversion code. Rename old killpg to my_killpg since
it has no use outside of win32.c. The psuedo-PID code in win32_kill also
played a factor in not writing a separate win32_killpg that calls
my_killpg. This fix is tested by kill0.t passing on
no-PERL_IMPLICIT_SYS builds.

[perl #121230]
Maintainers.pl synchronised for CPAN release of ExtUtils-Install
RMG - we no longer have UPSTREAM => 'undef' in Porting/Maintainers.pl
RMG - note that CPAN module upgrades are subject to code freeze restrictions

(As confirmed on p5p by RJBS on 24 March 2014.)
RMG - refer to BLEAD-POINT/BLEAD-FINAL releases for consistency and clarity
perldelta: /\C/ will be an error in 5.24

Update the recently added perldelta entry to say that /\C/ will become an
error rather than becoming equal to /./.
Commit b776cec188 missed these RMG steps when preparing Module::CoreList for 5.19.11
Start updating perldelta for 5.19.11