Optimize defragmentPage() in the case where the page contains either one or

two free-blocks and a small number of fragmented bytes.

FossilOrigin-Name: 4cd2a9672c59ea4b3b4cf3d2f139af3c18a8e833

diff --cc manifest
index c20fd94d764add9a8ed4011f18fe67118fea512c,c6196d9c48e5208a0f3ba1601f61e110cc9d4809..ffaf3dbb28c1fe4cb48a214f4512fd350c90e5bc
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Save\sa\sfew\sbytes\sand\sa\sfew\scycles\sby\ssetting\sVdbe.expmask\sto\szero\sfor\nstatements\sprepared\susing\slegacy\sinterface\ssqlite3_prepare().
- D 2017-02-23T16:30:16.521
 -C Tweak\sthe\scode\son\sthis\sbranch\sto\sdetect\sb-tree\spage\scorruption\sin\sthe\ssame\scases\sas\sthe\strunk.
 -D 2017-02-25T16:24:02.032
++C Optimize\sdefragmentPage()\sin\sthe\scase\swhere\sthe\spage\scontains\seither\sone\sor\ntwo\sfree-blocks\sand\sa\ssmall\snumber\sof\sfragmented\sbytes.
++D 2017-02-25T17:47:31.387
  F Makefile.in edb6bcdd37748d2b1c3422ff727c748df7ffe918
  F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
  F Makefile.msc a89ea37ab5928026001569f056973b9059492fe2
@@@ -1557,7 -1557,7 +1557,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P d6afd98de3ee8b714dfd6477ead955096f623972
- R d82d78a185c578681c4bad1233af7bd3
 -P 202b1c0276aec6b8da64d3277de1ad91c9d62d80
++P a8fd705258643863493476f8b42ee981608a339f f9863b39d96dce6cb5e49a5f3a445ff3d897a951
+ R 7a56121f7b6bd4c4a315ae4d10cd07e6
  U dan
- Z 013ae364526d4d7cd1569b7a9709f5c0
 -Z 0eab51f3ee55bc511deac00d1a02232c
++Z 1f9c94a7513412f3add97a95f1a8ec80

diff --cc manifest.uuid
index 36ee9348a99015fa3fddb6a543e83800c0346528,190b38aa8902f428c92f83a9848b6293a91bdc30..15d62e357c0c4263e42287a60ecc755179f35277
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- a8fd705258643863493476f8b42ee981608a339f
 -f9863b39d96dce6cb5e49a5f3a445ff3d897a951
++4cd2a9672c59ea4b3b4cf3d2f139af3c18a8e833