Remove the column-cache from the code generator. The column-cache has been

a persistent source of bugs for years and with recent improvements
in the performance of OP_Column, it no longer provides a benefit.  After
the column cache is removed, the binary is almost 2KB smaller and the
speed-check.sh performance test is over 3 million cycles faster.

FossilOrigin-Name: cdff3af7bedc5ebea04bd9b5e2112d3db451a475c18c9a9ebd45f6f3a89a43cb

diff --cc manifest
index 01b4b526f599a8747502cc0e7cc6534f1b60a3ce,bc76cd12e800a75c46583c5cc103ff4dc1ae0f98..ef52477198653ca54490cb2ff1479e911d6db266
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\stest\scases\sfor\sthe\sconstant\sexpression\sfix\sof\sthe\sprevious\scheck-in.
- D 2018-08-04T15:28:12.613
 -C Remove\sa\stestcase()\sthat\sis\sno\slonger\sreachable\swithout\sthe\scolumn\scache.\nProvide\san\sassert()\sto\shelp\sprove\sthat\sthe\stestcase\sis\sno\slonger\sreachable.
 -D 2018-08-04T20:12:10.289
++C Remove\sthe\scolumn-cache\sfrom\sthe\scode\sgenerator.\s\sThe\scolumn-cache\shas\sbeen\na\spersistent\ssource\sof\sbugs\sfor\syears\sand\swith\srecent\simprovements\nin\sthe\sperformance\sof\sOP_Column,\sit\sno\slonger\sprovides\sa\sbenefit.\s\sAfter\nthe\scolumn\scache\sis\sremoved,\sthe\sbinary\sis\salmost\s2KB\ssmaller\sand\sthe\nspeed-check.sh\sperformance\stest\sis\sover\s3\smillion\scycles\sfaster.
++D 2018-08-04T20:30:55.322
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F Makefile.in 0a3a6c81e6fcb969ff9106e882f0a08547014ba463cb6beca4c4efaecc924ee6
@@@ -449,8 -449,8 +449,8 @@@ F src/ctime.c b157b01081f92442f8b0218dd
  F src/date.c ebe1dc7c8a347117bb02570f1a931c62dd78f4a2b1b516f4837d45b7d6426957
  F src/dbpage.c 4aa7f26198934dbd002e69418220eae3dbc71b010bbac32bd78faf86b52ce6c3
  F src/dbstat.c edabb82611143727511a45ca0859b8cd037851ebe756ae3db289859dd18b6f91
- F src/delete.c 4c8c7604277a2041647f96b78f4b9a47858e9217e4fb333d35e7b5ab32c5b57f
- F src/expr.c 825198653fb655df3d758c556eb003f0a531a3661d0573cf445b4e9298daac07
+ F src/delete.c 107e28d3ef8bd72fd11953374ca9107cd74e8b09c3ded076a6048742d26ce7d2
 -F src/expr.c 3c5c439653cbe8a164af1e854379074153c38c222dbe812c01bdd72f507635c8
++F src/expr.c aac1c33ef8899d0cfe32e4269810e10372f8fdbce6554b38034973d5e8c285d9
  F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
  F src/fkey.c f59253c0be4b1e9dfcb073b6d6d6ab83090ae50c08b5c113b76013c4b157cd6a
  F src/func.c 7c288b4ce309b5a8b8473514b88e1f8e69a80134509a8c0db8e39c858e367e7f
@@@ -1754,7 -1754,7 +1754,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 8bc7f84c39f913b0b0f5e9f5fd9d7dd8bda8422248c069712b6992c32c759a83
- R 6932e89db01172dd37443d3c6c0ba024
 -P 2041231d56c7b02b785015ef4d1af260d61326eab1b2a304c17faa3e33f76441
 -R 23d677c80730de8e8fb9c53343c12875
++P 95db5bd9fea86a10c9528dd24841e1370dfdc0bbb5c98b7cbd808a8bc59dd48f a500893b6f64aced197cd32b79d51a481629a39d45dbcf0f02d65e5451ac4706
++R a895202b2ab9d783fc535831c38c174c
++T +closed a500893b6f64aced197cd32b79d51a481629a39d45dbcf0f02d65e5451ac4706
  U drh
- Z 944fd02700c6746ca58d0f2d1bfa9fb6
 -Z 0342b37d7a7258c5c8b069d39abadbfe
++Z 37d5cbe7046590064debd1c15a35aeb1

diff --cc manifest.uuid
index 682bfbbba333fd92aafbece6d94b4c31d8a8b6b1,a4af2ba5b7195fb97fe27b8a0693f2e0a1722da1..3398b5e9d33f37a0a5cb86127fe6da120d051ac1
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 95db5bd9fea86a10c9528dd24841e1370dfdc0bbb5c98b7cbd808a8bc59dd48f
 -a500893b6f64aced197cd32b79d51a481629a39d45dbcf0f02d65e5451ac4706
++cdff3af7bedc5ebea04bd9b5e2112d3db451a475c18c9a9ebd45f6f3a89a43cb

diff --cc src/expr.c
Simple merge