simd3.f90 and simd4.f90 fail only with -msse2.  But they are compiled
with -mavx on AVX machines.  Add 2 tests to compile simd3.f90 and
simd4.f90 with -msse2 on AVX machines.

	PR middle-end/71734
	* testsuite/libgomp.fortran/pr71734-1.f90: New test.
	* testsuite/libgomp.fortran/pr71734-2.f90: Likewise.

From-SVN: r237950