fix more array.tostring() removal issues in Python 3.9

Several shell.py script versions use the depreciated array.tostring() method,
which has been removed in Python 3.9. I changed these instances to .tobytes(),
and adjusted .ljust()'s second argument to be a byte string.

I also fixed a related issue, where #flash'ing from a shell.py which assumes a
2-cell wide Forth to a non-.hex file would error
because the unsigned short array returned from serialize() would be written to
file with assumptions of signed short:

open(dest, "wb").write(array.array("h", d).tobytes())

This would cause an overflow error. Changing "h" to "H" in that last code
snippet (in swapforth.py), lines up the signdedness.

j1a/nandland-go/shell.py

@@ -58,7 +58,7 @@ def serialize(self):
         for l in lines:
             l = l.split()
             s += [int(b, 16) for b in l[1:17]]
-        s = array.array('B', s).tostring().ljust(8192, chr(0xff))
+        s = array.array('B', s).tobytes().ljust(8192, bytes([0xFF]))
         return array.array('H', s)
 
 if __name__ == '__main__':

j1a/shell.py

@@ -65,7 +65,7 @@ def serialize(self):
         for l in lines:
             l = l.split()
             s += [int(b, 16) for b in l[1:17]]
-        s = array.array('B', s).tostring().ljust(8192, chr(0xff))
+        s = array.array('B', s).tobytes().ljust(8192, bytes([0xFF]))
         return array.array('H', s)
 
 if __name__ == '__main__':

j1a/verilator/shell.py

@@ -46,7 +46,7 @@ def serialize(self):
         for l in lines:
             l = l.split()
             s += [int(b, 16) for b in l[1:17]]
-        s = array.array('B', s).tostring().ljust(8192, chr(0xff))
+        s = array.array('B', s).tobytes().ljust(8192, bytes([0xFF]))
         return array.array('H', s)
 
 if __name__ == '__main__':

j1a/verilator/simshell4.py

@@ -46,7 +46,7 @@ def serialize(self):
         for l in lines:
             l = l.split()
             s += [int(b, 16) for b in l[1:17]]
-        s = array.array('B', s).tostring().ljust(8192, chr(0xff))
+        s = array.array('B', s).tobytes().ljust(8192, bytes([0xFF]))
         return array.array('H', s)
 
 if __name__ == '__main__':

shell/swapforth.py

@@ -200,12 +200,12 @@ def shellcmd(self, cmd):
                     if dest.endswith('.hex'):
                         open(dest, "w").write("".join(["%08x\n" % (x & 0xffffffff) for x in d]))
                     else:
-                        open(dest, "wb").write(array.array("i", d).tostring())
+                        open(dest, "wb").write(array.array("i", d).tobytes())
                 else:
                     if dest.endswith('.hex'):
                         open(dest, "w").write("".join(["%04x\n" % (x & 0xffff) for x in d]))
                     else:
-                        open(dest, "wb").write(array.array("h", d).tostring())
+                        open(dest, "wb").write(array.array("H", d).tobytes())
         elif cmd.startswith('#setclock'):
             n = datetime.utcnow()
             cmd = "decimal %d %d %d %d %d %d >time&date" % (n.second, n.minute, n.hour, n.day, n.month, n.year)