Allow UNION ALL sub-queriesto be flattened even if the parent query is a join.

FossilOrigin-Name: df1d6482f9e92dafdca1948e96eef52d8646eef9c356394afabe431d6357dd34

diff --cc manifest
index 1e99f333c3c7202d14db2ea9aeb32588b45a866f,5b84a2befe11e8eab06f4e20f08c51120f08c014..c174113104eadcabde9e84970f97c849804c0881
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C In\sthe\sCLI,\sadd\sthe\s".filectrl\sdata_version"\scommand.\s\sAnd\sput\sthe\svarious\n".filectrl"\ssubcommands\sin\salphabetical\sorder.
- D 2020-12-17T15:17:42.367
 -C Fix\sfor\sthe\sprevious\sfix\sin\sthe\scase\swhere\sa\sUNION\sALL\ssub-query\sis\sjoined\sagainst\ssome\sother\scompound\squery.
 -D 2020-12-18T18:04:44.749
++C Allow\sUNION\sALL\ssub-queriesto\sbe\sflattened\seven\sif\sthe\sparent\squery\sis\sa\sjoin.
++D 2020-12-19T13:58:06.688
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -540,8 -540,8 +540,8 @@@ F src/printf.c 30e92b638fac71dcd85cdea1
  F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
  F src/resolve.c 1948a92ca9eab776632816b97e57c61d933474a78aad4f4ef835c916a83dbb1c
  F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
- F src/select.c c9b68506e5d8cc8d0e4b307b97a9800b050ac37dada80ae9c66f680f8fac3e09
+ F src/select.c deeed19d210db99369cb66d6804c889426851d541484fcc35ad554a19859ae8d
 -F src/shell.c.in e9f674ee4ec6c345679e8a5b16c869c6c59eb1540dd98ac69e4736ecddce0090
 +F src/shell.c.in 6dd0d9260220f807d6d1b8e57dd6e163fe55bd0e97fa416c8c139162e3416134
  F src/sqlite.h.in 5b7593bb0f3658e682a9fcd1cd8fcedf244ec45ca93d645055a53172f55eb783
  F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
  F src/sqlite3ext.h 61b38c073d5e1e96a3d45271b257aef27d0d13da2bea5347692ae579475cd95e
@@@ -1891,7 -1893,7 +1893,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 2a6cd6833e44dd6a2ac388815f43be6508f6fa6db5e451e964276a6c87e6c5ae
- R 8fec60d5d4f6323f9e214e52e3dfbcc8
 -P c510377b0b052e400f2ee4f20220b61cdf74ee44b9bb9e6490787c88dd4c55aa
 -R 2a24a93078ef04ec108f14575de16445
 -U dan
 -Z c9e8c301310f3fe94971f95dfbdc7685
++P 3434452148eef39ba3ba2f40a6fedb6ec4f5157cbc2763b3ec90ec7f2b126382 63c5cfb9ae8f4598a523bed2a60c0e69172179952961a573113fcf756c06551d
++R 01abc47468d8209e3de01dce0ca29125
++T +closed 63c5cfb9ae8f4598a523bed2a60c0e69172179952961a573113fcf756c06551d
 +U drh
- Z 8df200953f9823684b5ad2b1a02406fd
++Z 9a839de521f6f5591d18cd2ba96a1b41

diff --cc manifest.uuid
index c23f193a3e2bc089b3f66bc6ae4e6147538d16dd,844ee2327545fca5fb396990ad3e13db13785515..516cbc030ec504d334b9b9654b70211220c51738
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 3434452148eef39ba3ba2f40a6fedb6ec4f5157cbc2763b3ec90ec7f2b126382
 -63c5cfb9ae8f4598a523bed2a60c0e69172179952961a573113fcf756c06551d
++df1d6482f9e92dafdca1948e96eef52d8646eef9c356394afabe431d6357dd34