sgefa: Fix invalid memory access

In test case 4 all elements of the row are zero such that
the loop is exited due to the i < n condition. However, before
we can check this condition, we first access out of bound memory.
Switching the conditions fixes this problem.

git-svn-id: https://llvm.org/svn/llvm-project/test-suite/trunk@200154 91177308-0d34-0410-b5e6-96231b3b80d8