Fix an assert() statement that was made obsolete by the constant

propagation enhancement.  Problem discovered by OSSFuzz.

FossilOrigin-Name: e4b4737e348235e196a45e1b71876b82e0cc836e1c5c16ea5f9333b7509b59b8

manifest

@@ -1,5 +1,5 @@
-C Improved\sdebugging\soutput\swhen\sthe\s".selecttrace"\soption\sis\sused\sin\sthe\sshell.
-D 2018-07-28T14:34:22.343
+C Fix\san\sassert()\sstatement\sthat\swas\smade\sobsolete\sby\sthe\sconstant\npropagation\senhancement.\s\sProblem\sdiscovered\sby\sOSSFuzz.
+D 2018-07-28T14:56:56.784
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 0a3a6c81e6fcb969ff9106e882f0a08547014ba463cb6beca4c4efaecc924ee6
@@ -498,7 +498,7 @@ F src/printf.c 7f6f3cba8e0c49c19e30a1ff4e9aeda6e06814dcbad4b664a69e1b6cb6e7e365
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c 797088662ed61102485e3070ba3b3f7828bd5ef6a588223ba6865d77d52f6cea
 F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
-F src/select.c a7c1a827d9bb23334b9bfe7e5c103b1398371f10796154a69023e0946fb3b0d9
+F src/select.c 22ed163cf65258a1101685228bb67d85b60b2965fec344f5c56d185f46fc62f2
 F src/shell.c.in f6ebd05c461805a7c708333cd645e74e0a93560d2118f5adb73a75d8c9cf6b01
 F src/sqlite.h.in c6451bb876adced3aba5b1682c6317d215c5eceaba21a6ce979e71a0b8d0bf95
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -954,7 +954,7 @@ F test/fuzzdata1.db 7ee3227bad0e7ccdeb08a9e6822916777073c664
 F test/fuzzdata2.db f03a420d3b822cc82e4f894ca957618fbe9c4973
 F test/fuzzdata3.db c6586d3e3cef0fbc18108f9bb649aa77bfc38aba
 F test/fuzzdata4.db 1882f0055fb63214d8407ddc7aca9b0b1c59af21
-F test/fuzzdata5.db 117d821cde02e30a687f6361a34b98e6e0b05062df523cfee163c58564403b68
+F test/fuzzdata5.db e60076888dd070ac3cd39b46c566176173c392042622ced6f7df465bd6c84887
 F test/fuzzdata6.db 92a80e4afc172c24f662a10a612d188fb272de4a9bd19e017927c95f737de6d7
 F test/fuzzer1.test 3d4c4b7e547aba5e5511a2991e3e3d07166cfbb8
 F test/fuzzer2.test a85ef814ce071293bce1ad8dffa217cbbaad4c14
@@ -1753,7 +1753,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 02204f8b246c868846f39bd44f2e3bc0fab0275aa09ef3a0e5a8e3d58f484ca8
-R 7a41e2fa4afa4ef4cbf53d2695995d58
+P fcb88dd6b0f248f600c1158907889f6d5fa2c96eb4585221941da4673c6db6eb
+R 4bd85098ffd81dad632d50502c6e83b7
 U drh
-Z 25d0f8749ae2cbe0cb0dae376846dc8c
+Z 583b66bbd6725fdec089b65fdf480429

manifest.uuid

@@ -1 +1 @@
-fcb88dd6b0f248f600c1158907889f6d5fa2c96eb4585221941da4673c6db6eb
+e4b4737e348235e196a45e1b71876b82e0cc836e1c5c16ea5f9333b7509b59b8

src/select.c

@@ -3450,7 +3450,7 @@ static Expr *substExpr(
       Expr *pCopy = pSubst->pEList->a[pExpr->iColumn].pExpr;
       Expr ifNullRow;
       assert( pSubst->pEList!=0 && pExpr->iColumn<pSubst->pEList->nExpr );
-      assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+      assert( pExpr->pRight==0 );
       if( sqlite3ExprIsVector(pCopy) ){
         sqlite3VectorErrorMsg(pSubst->pParse, pCopy);
       }else{