run testing instructions from MDL-38923 on 26.
backport MDL-38923 to 2.6
Bootstrap base two column layout all blocks docked content width doesn't adjust
Cannot dock blocks with Bootstrapbase/clean theme
MDL-39824 missed setting correct span calculations for 768px-979px and 1200px+ displays.
Blocks in the right columns are larger in RTL
In RTL the 'Undock all' icon should be inverted in Bootstrapbase themes