[Darwin, testsuite] Fix framework-1.c on later Darwin.

The test works by checking that a known framework path is accessible
when the '-F' option is given.  We need to find a framework path that
exists across a range of Darwin versions, and parseable by GCC.  This
adjusts the test to use a header path that exists and is parsable from
Darwin9 through Darwin19.

gcc/testsuite/ChangeLog:

2019-11-06  Iain Sandoe  <iain@sandoe.co.uk>

	* gcc.dg/framework-1.c: Adjust test header path.

From-SVN: r277892

gcc/testsuite/ChangeLog

+2019-11-06  Iain Sandoe  <iain@sandoe.co.uk>
+
+	* gcc.dg/framework-1.c: Adjust test header path.
+
 2019-11-06  Claudiu Zissulescu  <claziss@synopsys.com>
 	Sahahb Vahedi  <shahab@synopsys.com>
 	Cupertino Miranda  <cmiranda@synopsys.com

gcc/testsuite/gcc.dg/framework-1.c

 /* { dg-do compile { target *-*-darwin* } } */
 /* { dg-options "-F." } */
 
-#include <Carbon/Carbon.h>
+#include <Kernel/string.h>