Attempt to optimize "x IS NULL" and "x IS NOT NULL" expressions when x is a column...

FossilOrigin-Name: de9c86c9e4cdb34f4b7d65f160d1e589fb969bbf64c66d2b24c502d1ee424dbb

diff --cc manifest
index 877ec2b56e726e2e0ad51c328644aca23d4dcddf,7e347fdfbe3617fd181ebaad964b1fce6544bc8c..8b95e294e475f55fcbe366f84c63a7005c62e8f7
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Minor\ssimplification\sin\sresolve.c.
- D 2021-02-26T15:20:17.903
+ C Attempt\sto\soptimize\s"x\sIS\sNULL"\sand\s"x\sIS\sNOT\sNULL"\sexpressions\swhen\sx\sis\sa\scolumn\swith\sa\sNOT\sNULL\sconstraint.
 -D 2021-02-26T20:14:32.131
++D 2021-02-26T20:39:08.934
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1907,7 -1908,10 +1908,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 062b338ff2ea71633b4fb3c75c6a47b5fc4fe9c2a72daacd987d1eca0bda5217
- R 07651de30eadccb5d0a1b765b39186be
 -P 310dac342e7b1f9b5a5df6a9d598e85d5fef59bba9307d9230baf77c8f2351a2
++P 310dac342e7b1f9b5a5df6a9d598e85d5fef59bba9307d9230baf77c8f2351a2 5ecd842555009ce27ee6390325ac5c2504143474b12b730933f0833b3dad788a
+ R 5da9c9b015e5cf6e85f36d061ac9c73d
 -T *branch * ifnull-opt
 -T *sym-ifnull-opt *
 -T -sym-trunk *
++T +closed 5ecd842555009ce27ee6390325ac5c2504143474b12b730933f0833b3dad788a
  U dan
- Z a8b3d49e868cbc0b6002cfdac6e7fd25
 -Z 9cbe82fbe7c5328bb13207c38d4a331e
++Z 563142b6d6e036f424233eef5aeb4af2

diff --cc manifest.uuid
index e486d4c31974205f515853d04b9c7303df4dc4c4,795d6c15adceca716e517a38eb3a68a7d70637f3..b039706b466574dbe9972b2af33f1d2b71153518
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 310dac342e7b1f9b5a5df6a9d598e85d5fef59bba9307d9230baf77c8f2351a2
 -5ecd842555009ce27ee6390325ac5c2504143474b12b730933f0833b3dad788a
++de9c86c9e4cdb34f4b7d65f160d1e589fb969bbf64c66d2b24c502d1ee424dbb