[Offload][OpenMP] Tests require libc on GPU for printf (#155785)

These tests currently fail when libc is not configured to be built as
they require printf to be available in target regions.

Author: jplehr

offload/test/mapping/map_ptr_and_star_global.c

@@ -1,5 +1,7 @@
 // RUN: %libomptarget-compilexx-run-and-check-generic
 
+// REQUIRES: libc
+
 #include <omp.h>
 #include <stdio.h>
 

offload/test/mapping/map_ptr_and_star_local.c

@@ -1,5 +1,7 @@
 // RUN: %libomptarget-compilexx-run-and-check-generic
 
+// REQUIRES: libc
+
 #include <omp.h>
 #include <stdio.h>
 

offload/test/mapping/map_ptr_and_subscript_global.c

@@ -1,5 +1,7 @@
 // RUN: %libomptarget-compilexx-run-and-check-generic
 
+// REQUIRES: libc
+
 #include <omp.h>
 #include <stdio.h>
 

offload/test/mapping/map_ptr_and_subscript_local.c

@@ -1,5 +1,7 @@
 // RUN: %libomptarget-compilexx-run-and-check-generic
 
+// REQUIRES: libc
+
 #include <omp.h>
 #include <stdio.h>
 

offload/test/mapping/map_structptr_and_member_global.c

@@ -1,5 +1,7 @@
 // RUN: %libomptarget-compilexx-run-and-check-generic
 
+// REQUIRES: libc
+
 #include <omp.h>
 #include <stdio.h>
 

offload/test/mapping/map_structptr_and_member_local.c

@@ -1,5 +1,7 @@
 // RUN: %libomptarget-compilexx-run-and-check-generic
 
+// REQUIRES: libc
+
 #include <omp.h>
 #include <stdio.h>