Refactor the sqlite3VdbeRecordCompare() routine used to compare btree records.

Create fast-track special case routines to handle the common cases more
quickly.  This gives a significant performance boost.

FossilOrigin-Name: 3325ad5bdc2f81f63b556d6f4d0589d89b142b2b

diff --cc manifest
index 4cca5ef21aaba2ee2585c01c2a407d5b0c17a654,61023f47d0c52198ed28d9cffcf12e595380aca7..6590df81690c2f37e2b959cf0f6119f9e72623b7
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Change\san\sOP_SCopy\sinto\san\sOP_Copy\sin\sa\scase\swhere\sthe\sdestination\smight\sbe\nused\safter\sthe\ssource\shas\schanged.
- D 2014-03-03T17:36:39.940
 -C Fix\smore\sinstances\sof\sassuming\s'char'\sis\ssigned.\s\sAnd,\smake\ssure\sto\snever\sshift\na\ssigned\sinteger.
 -D 2014-03-04T04:04:33.269
++C Refactor\sthe\ssqlite3VdbeRecordCompare()\sroutine\sused\sto\scompare\sbtree\srecords.\nCreate\sfast-track\sspecial\scase\sroutines\sto\shandle\sthe\scommon\scases\smore\nquickly.\s\sThis\sgives\sa\ssignificant\sperformance\sboost.
++D 2014-03-04T04:12:56.404
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in 2ef13430cd359f7b361bb863504e227b25cc7f81
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -1153,7 -1154,7 +1154,8 @@@ F tool/vdbe_profile.tcl 67746953071a9f8
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
  F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
- P 559835e54e0715f2b4d207d056199a8268af739e
- R 0f407d04c62b2be5f5455aa20c5e914d
 -P 979da752e6f8767a61a8efed824ffad9605d0f4c
++P c0fa0c0e2de50d7eda19ab8862496b18eff93538 f10130ede433a19b3945753f23962871c8d2dcf3
+ R 76afae803c9615945e7c1ed11c396a45
++T +closed f10130ede433a19b3945753f23962871c8d2dcf3
  U drh
- Z c144dcb8dd86ca2b393613351986e190
 -Z 4679453e8217252329a19e88ce1ddc0d
++Z ac0c95f2ad16dfe0178099b125074c2f

diff --cc manifest.uuid
index 097e35067a4b8ed661235619db20bbedc5f8d5eb,b38b734ab936553f899d49d8600ec568fd6ffb98..3c00b464cffe9e2810754a9512d7a6a386595951
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- c0fa0c0e2de50d7eda19ab8862496b18eff93538
 -f10130ede433a19b3945753f23962871c8d2dcf3
++3325ad5bdc2f81f63b556d6f4d0589d89b142b2b