x509asn1: improve encodeOID

- return error on zero length input
- return error on OOM or doing too large output
- fix full 32-bit number support
- fix the broken handling of the first and second numbers
- support up to 32-bit minus 80 for the second number
- a field with a leading 0x80 is now considered an error, since it only
  works as padding and is then no longer the shortest possible version

Add unit tests in 1666

Bonus: removed the last argument to OID2str() as it was always set TRUE.

Closes #21003

tests/data/Makefile.am

@@ -222,6 +222,7 @@ test1640 test1641 test1642 test1643 \
 \
 test1650 test1651 test1652 test1653 test1654 test1655 test1656 test1657 \
 test1658 test1659 test1660 test1661 test1662 test1663 test1664 test1665 \
+test1666 \
 \
 test1670 test1671 \
 \

tests/data/test1666

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="US-ASCII"?>
+<testcase>
+<info>
+<keywords>
+unittest
+encodeOID
+x509asn1
+</keywords>
+</info>
+
+# Client-side
+<client>
+<features>
+unittest
+</features>
+<name>
+encodeOID unit tests
+</name>
+</client>
+</testcase>