Speed and (slightly) simplify shell's input line early processing.

FossilOrigin-Name: a1c7f7f8e1b46440234be96e813e4c2c28150413dd95dcab5d13b9c80a202edf

diff --cc manifest
index 1fc3e72396ed935a0a385ad0713983234105b15b,990a0ef0bcd05d226536a67ce2863640ca87f5b3..ae06b31714546227d064a627bed9a225bf825cc5
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\sthe\s"PRAGMA\stable_list"\scommand\swith\sits\scorresponding\seponymous\ntable-valued\sfunction:\s"pragma_table_list".
- D 2021-09-21T17:26:23.956
 -C Adjust\sshell\stests\sfor\s*Nix\sand\sWindows\stest\splatform\sanomaly
 -D 2021-09-19T18:31:55.750
++C Speed\sand\s(slightly)\ssimplify\sshell's\sinput\sline\searly\sprocessing.
++D 2021-09-21T19:19:28.756
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -1925,7 -1925,7 +1925,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P af5dcc9c2a3a45d10b985f6b7ea18d39c75502ed10fa6496aad787dbe8c8c3fb
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- U drh
- Z cb33f0f0128d5123d146e61157efe535
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++P 2c0e7ae541e9ecb86aa58fa7e7057def8aac1b1af1af1aa80b8bf2d260f9a2f9 577544c5a2f193e00e5ca55b7feae96568198019573b9b0b37e2bf4300d6d524
++R 3f0f5d8f4d6753399cf7fbd70ddb9c72
+ U larrybr
 -Z c20e0c055c38369d11323498c4dfd701
++Z da72ab7831c9560c80854036f35fcf46

diff --cc manifest.uuid
index 544944c85b8406d98ba38155be312dd2c2294afa,3d8514f0573ee5142f13673381f77ba060072c19..e1012aaf49f63c561c72a052bd49f8b91c225390
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- 2c0e7ae541e9ecb86aa58fa7e7057def8aac1b1af1af1aa80b8bf2d260f9a2f9
 -577544c5a2f193e00e5ca55b7feae96568198019573b9b0b37e2bf4300d6d524
++a1c7f7f8e1b46440234be96e813e4c2c28150413dd95dcab5d13b9c80a202edf