Make sure all virtual table cursors have been closed on a prepared statement

prior to unlinking the perpared statement from its database connection.
The test case for this is in TH3, in the main39.test module.

FossilOrigin-Name: 6d42d806adb833572a324d4141ab3b2c315617b2

diff --cc manifest
index f8fd1b8f9e78b7abcd6fd87e56ba1e3e9900823f,d8b5eccde7596e8ea107dc90e606f91089357bc3..76b0c2b169ae601348532f76dd8a518932455f03
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Fix\sa\sbug\sin\sfts3\scausing\sit\sto\sreturn\sSQLITE_NOMEM\swhen\sNEAR,\sOR\sand\ssome\sauxiliary\sfunctions\swere\sused\stogether.\sAlso\sa\ssegfault\sin\svtab.c\sthat\scould\sfollow\san\sOOM\scondition.
- D 2012-10-25T19:25:39.022
 -C Make\ssure\sall\svirtual\stable\scursors\shave\sbeen\sclosed\son\sa\sprepared\sstatement\nprior\sto\sunlinking\sthe\sperpared\sstatement\sfrom\sits\sdatabase\sconnection.
 -D 2012-10-26T00:11:23.970
++C Make\ssure\sall\svirtual\stable\scursors\shave\sbeen\sclosed\son\sa\sprepared\sstatement\nprior\sto\sunlinking\sthe\sperpared\sstatement\sfrom\sits\sdatabase\sconnection.\nThe\stest\scase\sfor\sthis\sis\sin\sTH3,\sin\sthe\smain39.test\smodule.
++D 2012-10-26T00:55:07.323
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in 5f4f26109f9d80829122e0e09f9cda008fa065fb
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -1021,7 -1021,10 +1021,7 @@@ F tool/vdbe-compress.tcl f12c884766bd14
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
  F tool/win/sqlite.vsix 67d8a99aceb56384a81b3f30d6c71743146d2cc9
- P a6d906cfeb9b181fd5b88df3650bab7ee1a24c0b
- R 674e19925b07366510d1fc7375732e22
- U dan
- Z 1032beb5eac48ad97bee39ee66a1a525
 -P 33f4f9817e8b3cb97ce02a4c49bd586332da37b2
++P 33f4f9817e8b3cb97ce02a4c49bd586332da37b2 f7c5abe8739090db0738d2c7002a0d71f76c927e
+ R bc72b67b42140060c43fae49b44a7daa
 -T *branch * deferred-close-order
 -T *sym-deferred-close-order *
 -T -sym-trunk *
+ U drh
 -Z 48246a4a15ab765f01b398ae16f882b2
++Z d0356ac18ea49d0169f59bb16fb002ee

diff --cc manifest.uuid
index 6014f84bdbb1e001d321aa7ac9dc6a3e1e8a0992,78af04e8abaef26368500c757f22c653ee63a836..31631389380721da5d27ce5043a5f749c320c02c
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 33f4f9817e8b3cb97ce02a4c49bd586332da37b2
 -f7c5abe8739090db0738d2c7002a0d71f76c927e
++6d42d806adb833572a324d4141ab3b2c315617b2