gfortran.dg/gomp/pr99226.f90: Add missing dg-error

Follow up to r14-2754-g2e31fe431b08b0302e1fa8a1c18ee51adafd41df
which added a check that a target region with teams does not
have anything anything else strictly nested in the target.

When changing the dg-error for this PR, somehow the addition of a
dg-error in a second line was lost (the message uses (1) and (2) as
location, showing two lines, both need a dg-error with the same message).

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/pr99226.f90: Update dg-error.