[libgomp] In OpenACC testing, by default only build for the offload target that we're actually going to test
... to avoid compilation overhead, and to keep simple '-foffload=[...]'
handling in test cases.
libgomp/
* testsuite/libgomp.oacc-c++/c++.exp: Specify
"-foffload=$offload_target".
* testsuite/libgomp.oacc-c/c.exp: Likewise.
* testsuite/libgomp.oacc-fortran/fortran.exp: Likewise.
* testsuite/lib/libgomp.exp
(check_effective_target_openacc_nvidia_accel_configured): Remove,
as (conceptually) merged into
check_effective_target_openacc_nvidia_accel_selected. Adjust all
users.
From-SVN: r269109
