Restrict 'c-c++-common/goacc/mdc-1.c' to LP64, LLP64

The tree dump scanning has certain expectations.

	gcc/testsuite/
	* c-c++-common/goacc/mdc-1.c: Restrict to LP64, LLP64.

From-SVN: r279720

gcc/testsuite/ChangeLog

+2019-12-23  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* c-c++-common/goacc/mdc-1.c: Restrict to LP64, LLP64.
+
 2019-12-23  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR c++/92789

gcc/testsuite/c-c++-common/goacc/mdc-1.c

 /* Test OpenACC's support for manual deep copy, including the attach
    and detach clauses.  */
 
-/* { dg-do compile { target int32 } } */
+/* TODO The tree dump scanning has certain expectations.
+   { dg-do compile { target { lp64 || llp64 } } } */
 /* { dg-additional-options "-fdump-tree-omplower" } */
 
 void