If a writer crashes in WAL mode and leave the SHM file in an inconsistent state,

subsequent transactions are now able to recover the SHM file even if there are
active read transactions.

FossilOrigin-Name: ee8a108058c304f9b6b02f84f1da01a0b7a3a21992627bcc1f97d42e8d23da69

diff --cc manifest
index 80b02e2e4b1d2a586d3e5a52ef4348694e43bbc3,ef7faf53dc8176b420465523ead6952524c957dd..ac6aa6536a938309926c2d8cd1d088729195464a
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Remove\sa\ssurplus\sspace\sfrom\sa\scomment
- D 2020-07-24T11:01:29.118
 -C Add\san\ssqlite3FaultSim()\sto\smake\san\sOOM\scase\smore\saccessible\sand\sremove\nthe\sALWAYS()\son\sthe\sconditional\sthat\sis\sfalse\swhen\sthe\sOOM\sactually\soccurs.
 -D 2020-07-28T17:17:36.521
++C If\sa\swriter\scrashes\sin\sWAL\smode\sand\sleave\sthe\sSHM\sfile\sin\san\sinconsistent\sstate,\nsubsequent\stransactions\sare\snow\sable\sto\srecover\sthe\sSHM\sfile\seven\sif\sthere\sare\nactive\sread\stransactions.
++D 2020-07-28T17:29:13.292
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1878,7 -1878,7 +1878,8 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P 270ac1a0f232d75537be40abae559004e950b992cb2c7e94cd6de66e96ae17bd
- R 0212ebf857b7a36fab6e1708725a20d6
 -P 7052cf1d533f6404d0f45cf0b3e8a11c1ee27eccb64680a7fd308c8da7cbd544
++P 73fecc688ab5c459245c9bb89432139a083ef378404b4dae3397a7f4e253f72a 2a251af84ff1f5ca281aa69c5410d6ae7aa5a85ef47149909a297525e1651e9d
+ R 69a29ce092f5af857bcf59873f5056ae
++T +closed 2a251af84ff1f5ca281aa69c5410d6ae7aa5a85ef47149909a297525e1651e9d
  U drh
- Z 7c8911d20a18c22808c4eb3363f6ff12
 -Z e3e8c0f9a7476656806546b877310ca8
++Z f0509e0a6ac22a3eb269a4a65f129fe3

diff --cc manifest.uuid
index ef6483f2d60cc1f1587b013bc23ec10d9e47eb1b,083a662fb35522a86f27a998595f2b07f3121260..f9787d86e374b12de76c39343bace1d24c745868
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 73fecc688ab5c459245c9bb89432139a083ef378404b4dae3397a7f4e253f72a
 -2a251af84ff1f5ca281aa69c5410d6ae7aa5a85ef47149909a297525e1651e9d
++ee8a108058c304f9b6b02f84f1da01a0b7a3a21992627bcc1f97d42e8d23da69