Performance optimization on balance_nonroot() and related routines.

2.6% faster overall with a size increase of less than 750 bytes.

FossilOrigin-Name: 25131e7062125e91c2d60ed2cadf134dd7609124

diff --cc manifest
index ab6b39e46a7cd6fe8dfb938a9034ac7549f17df7,718b155db27d661e0e3639b5950f5bf6ed57e277..5cd22e21a67acefaaea56dcd47e421b3edb46944
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Mark\ssome\sbranches\sas\sunreachable\safter\sthe\srecent\schange\sthat\srecognizes\nmismatch\sresult\sset\ssizes\son\scompound\sSELECT\sstatements\ssooner.
- D 2015-06-23T23:31:52.120
 -C Testability\simprovement.
 -D 2015-06-23T21:35:28.724
++C Performance\soptimization\son\sbalance_nonroot()\sand\srelated\sroutines.\n2.6%\sfaster\soverall\swith\sa\ssize\sincrease\sof\sless\sthan\s750\sbytes.
++D 2015-06-24T00:05:45.705
  F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
  F Makefile.in 1063c58075b7400d93326b0eb332b48a54f53025
  F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@@ -1286,7 -1286,7 +1286,8 @@@ F tool/vdbe_profile.tcl 67746953071a9f8
  F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
  F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
  F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
- P 4df852ce26c95d5d23c83dbe9c59d2c3435acddf
- R f33f66149dfc88305222eaacd7fef5a8
 -P f77f2f48f48e374a72b6c054142f7a3ec0b1483c
 -R 4d132507809128fd95303043fe3c27fc
++P c8d1f305b6e9dfc36b8e3f4ab92de4457884d903 eed6a3314518cdab809264284d7680385f0d5d2a
++R 89850ed2148a00ac2d9831c087418020
++T +closed eed6a3314518cdab809264284d7680385f0d5d2a
  U drh
- Z fe73de6bdd6d9128d20e7fa5150f1b6d
 -Z 2d888246a6aeb99138896a0f8b9aa3e8
++Z 115864ffd982466ffd849126735907ac

diff --cc manifest.uuid
index 797478ecf73260f29366fc68c0e82073e6d62475,62fd6afdb31878e2e7bb4815f5883dab3729da49..4c4df142b24490b7f3beda07be32be2a710ad2a3
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- c8d1f305b6e9dfc36b8e3f4ab92de4457884d903
 -eed6a3314518cdab809264284d7680385f0d5d2a
++25131e7062125e91c2d60ed2cadf134dd7609124