Run GCC7 regressions when GCC<7 OR dev tests on

 - Better/accurate logic to control when open GCC7 regressions are run
 - Moved `co_reduce_string` test to be with other `co_reduce...` tests

Author: zbeekman

CMakeLists.txt

@@ -560,6 +560,7 @@ if(opencoarrays_aware_compiler)
   add_mpi_test(duplicate_syncimages 8 ${tests_root}/unit/sync/duplicate_syncimages)
   add_mpi_test(co_reduce 4 ${tests_root}/unit/collectives/co_reduce_test)
   add_mpi_test(co_reduce_res_im 4 ${tests_root}/unit/collectives/co_reduce_res_im)
+  add_mpi_test(co_reduce_string 4 ${tests_root}/unit/collectives/co_reduce_string)
   add_mpi_test(syncimages_status 8 ${tests_root}/unit/sync/syncimages_status)
   add_mpi_test(sync_ring_abort_np3 3 ${tests_root}/unit/sync/sync_image_ring_abort_on_stopped_image)
   add_mpi_test(sync_ring_abort_np7 7 ${tests_root}/unit/sync/sync_image_ring_abort_on_stopped_image)
@@ -578,16 +579,17 @@ if(opencoarrays_aware_compiler)
     # GFortran PR 78505 only fixed on trunk/gcc 7
     add_mpi_test(source-alloc-no-sync 8 ${tests_root}/regression/reported/source-alloc-sync)
   endif()
-  if (CAF_RUN_DEVELOPER_TESTS OR $ENV{OPENCOARRAYS_DEVELOPER})
+
+  # Open GCC 7 regressions
+  if ((CAF_RUN_DEVELOPER_TESTS OR $ENV{OPENCOARRAYS_DEVELOPER}) OR (gfortran_compiler AND (CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 7.0.0)))
     add_mpi_test(convert-before-put 3 ${tests_root}/regression/reported/convert-before-put)
+    add_mpi_test(put-alloc-comp 2 ${tests_root}/regression/reported/issue-422-send)
+    add_mpi_test(get-put-alloc-comp 3 ${tests_root}/regression/reported/issue-422-send-get)
   endif()
   add_mpi_test(event-post 3 ${tests_root}/regression/reported/event-post)
   add_mpi_test(co_reduce-factorial 4 ${tests_root}/regression/reported/co_reduce-factorial)
   add_mpi_test(co_reduce-factorial-int8 4 ${tests_root}/regression/reported/co_reduce-factorial-int8)
   add_mpi_test(co_reduce-factorial-int64 4 ${tests_root}/regression/reported/co_reduce-factorial-int64)
-  add_mpi_test(put-alloc-comp 2 ${tests_root}/regression/reported/issue-422-send)
-  add_mpi_test(get-put-alloc-comp 3 ${tests_root}/regression/reported/issue-422-send-get)
-  add_mpi_test(co_reduce_string 4 ${tests_root}/unit/collectives/co_reduce_string)
 
   # IMAGE FAIL tests
   if(NOT CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 7)