Fix process substitution combined with redirection (#40)

The code for handling process substitution with redirection was
never being run because IORAW is usually set when IOPROCSUB is
set. This commit fixes the problem by moving the required code
out of the !IORAW if statement. The following command now prints
'good' instead of writing 'ok' to a bizzare file:

$ ksh -c 'echo ok > >(sed s/ok/good/); wait'
good

This commit also fixes a bug that caused the process ID of the
asynchronous process to print when the shell was in interactive
mode. The following command no longer prints a process ID,
behaving like in Bash and zsh:

$ echo >(true)
/dev/fd/5

src/cmd/ksh93/sh/args.c:
 - Temporarily turn off the interactive state while in a process
   substitution to prevent the shell from printing the PID of
   the asynchronous process.

src/cmd/ksh93/sh/io.c:
 - Move the code for process substitution with redirection into
   a separate if statement.

src/cmd/ksh93/tests/io.sh:
 - Add two tests for both process substitution bugs fixed by this
   commit.

src/cmd/ksh93/tests/shtests:
 - Update shtests with a patch from Martijn Dekker to use
   pretty-printing for the output from the times builtin (if it
   is available).

Fixes #2

src/cmd/ksh93/include/version.h

@@ -17,4 +17,4 @@
 *                  David Korn <dgk@research.att.com>                   *
 *                                                                      *
 ***********************************************************************/
-#define SH_RELEASE	"93u+m 2020-06-22"
+#define SH_RELEASE	"93u+m 2020-06-23"