If find is set to search a directory containing three other directories which
contain the folder ”bug” and to execute pwd in every folder containing the
folder ”bug” (-name bug -execdir pwd \;), then find prints the first directory
three times. The reason is that the working directory specified in
execp->wd_for_exec is set only once (pred.c:513-527) and never updated. 

Examples of Correct Fixes: 
1) Correct buggy if-condition by substituting excep->wd_for_exec by
execp->todo. 

2) If is exec_in_local_dir, then always reallocate execp->wd_for_exec and
remove the assertion. 

Example of Incorrect Fix: 
Remove if-condition such that it always redefines execp->wd_for_exec and keep
assertion that execp->todo is false (Regression because execp->todo might be
true such that assertion may fail).
