fixes issue 1023
fixes issue 1023

+ Remove the old pre-i#806 trace mangle check for bb end with no exit cti,
  which is no longer necessary and ends up doing the wrong thing for bbs
  located in the landing pad with translations pointing at their hook
  targets.
+ Relax the usage error on trace bb translation sources for landing pad
  bbs, which have translations pointing at their hook targets.

git-svn-id: ed337ca7cdb08c0ba29d8fe58632bb7686892c2d@1781 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6

rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio