Make TAP tests work on Windows.

On Windows, use listen_address=127.0.0.1 to allow TCP connections. We were
already using "pg_regress --config-auth" to set up HBA appropriately. The
standard_initdb helper function now sets up the server's
unix_socket_directories or listen_addresses in the config file, so that
they don't need to be specified in the pg_ctl command line anymore. That
way, the pg_ctl invocations in test programs don't need to differ between
Windows and Unix.

Add another helper function to configure the server's pg_hba.conf to allow
replication connections. The configuration is done similarly to "pg_regress
--config-auth": trust on domain sockets on Unix, and SSPI authentication on
Windows.

Replace calls to "cat" and "touch" programs with built-in perl code, as
those programs don't normally exist on Windows.

Add instructions in the docs on how to install IPC::Run on Windows. Adjust
vcregress.pl to not replace PERL5LIB completely in vcregress.pl, because
otherwise cannot install IPC::Run in a non-standard location easily.

Michael Paquier, reviewed by Noah Misch, some additional tweaking by me.

doc/src/sgml/install-windows.sgml

@@ -439,6 +439,7 @@ $ENV{CONFIG}="Debug";
 <userinput>vcregress modulescheck</userinput>
 <userinput>vcregress ecpgcheck</userinput>
 <userinput>vcregress isolationcheck</userinput>
+<userinput>vcregress tapcheck</userinput>
 <userinput>vcregress upgradecheck</userinput>
 </screen>
 
@@ -451,6 +452,29 @@ $ENV{CONFIG}="Debug";
    For more information about the regression tests, see
    <xref linkend="regress">.
   </para>
+
+  <para>
+   Running the TAP regression tests, with "vcregress tapcheck", requires an
+   additional Perl module to be installed:
+   <variablelist>
+    <varlistentry>
+     <term><productname>IPC::Run</productname></term>
+     <listitem><para>
+      As of this writing, <literal>IPC::Run</> is not included in the
+      ActiveState Perl installation, nor in the ActiveState Perl Package
+      Manager (PPM) library. To install, download the
+      <filename>IPC-Run-&lt;version&gt;.tar.gz</> source archive from CPAN,
+      at <ulink url="http://search.cpan.org/dist/IPC-Run/"></>, and
+      uncompress. Edit the <filename>buildenv.pl</> file, and add a PERL5LIB
+      variable to point to the <filename>lib</> subdirectory from the
+      extracted archive. For example:
+<programlisting>
+$ENV{PERL5LIB}=$ENV{PERL5LIB} . ';c:\IPC-Run-0.94\lib';
+</programlisting>
+     </para></listitem>
+    </varlistentry>
+   </variablelist>
+  </para>
  </sect2>
 
  <sect2>