testsuite: fix dg-require-effective-target order vs dg-additional-sources

testsuite: fix dg-require-effective-target order vs dg-additional-sources

Per gccint, 'dg-require-effective-target' must come before any
'dg-additional-sources' directives. Fix a handful of deviant cases.

gcc/testsuite/ChangeLog:
	* gcc.target/aarch64/aapcs64/func-ret-3.c: Fix dg-require-effective-target directive order.
	* gcc.target/aarch64/aapcs64/func-ret-4.c: Likewise.
	* gfortran.dg/PR100914.f90: Likewise.

libgomp/ChangeLog:
	* testsuite/libgomp.c++/pr24455.C: Fix dg-require-effective-target directive order.
	* testsuite/libgomp.c/pr24455.c: Likewise.