test-ranap: fix missing free in test_aper_causemisc, fixes expout

After aper_decode(), we still need to free the decoded struct.

This was introduced in 14da5411a4fbe05eccff5b4f0934d52773a3f97a
("test-ranap: Add test case about constrained integer range decode")

Note, in that commit there is another test failure in expout (a reversed byte
order) which is "secretly" fixed in bb289e3b810683dadc5e2dd0b345b97cd3e8bddb
("RAB parameters: add Extended Max Bitrate").

This commit fixes:

@@ -213,6 +212,7 @@
 </RANAP_IE>
 00 0a 00 11 00 00 01 00 29 40 0a 00 00 01 00 28 40 03 05 c2 d0
 report
-talloc report on 'asn1_context' (total      0 bytes in   1 blocks)
+talloc report on 'asn1_context' (total     40 bytes in   2 blocks)
+    constr_CHOICE.c:927            contains     40 bytes in   1 blocks (ref 0) 0x187e690
 talloc report on 'msgb' (total      1 bytes in   1 blocks)
 exit
1 file changed