[Committed, AArch64] Disable tests for ilp32.

Currently Return Address Signing is only supported in lp64. Thus the
tests that I added recently (that enables return address signing by the
mbranch-protection=standard option), should also be exempted from testing in
ilp32. This patch adds the needed dg-require-effective-target directive in the
tests.

*** gcc/testsuite/ChangeLog ***

2019-01-10  Sudakshina Das  <sudi.das@arm.com>

	* gcc.target/aarch64/bti-1.c: Exempt for ilp32.
	* gcc.target/aarch64/bti-2.c: Likewise.
	* gcc.target/aarch64/bti-3.c: Likewise.

Committed as obvious.

From-SVN: r267818

gcc/testsuite/ChangeLog

+2019-01-10  Sudakshina Das  <sudi.das@arm.com>
+
+	* gcc.target/aarch64/bti-1.c: Exempt for ilp32.
+	* gcc.target/aarch64/bti-2.c: Likewise.
+	* gcc.target/aarch64/bti-3.c: Likewise.
+
 2019-01-10  Stefan Agner  <stefan@agner.ch>
 
 	PR target/88648

gcc/testsuite/gcc.target/aarch64/bti-1.c

 /* { dg-do compile } */
 /* -Os to create jump table.  */
 /* { dg-options "-Os" } */
+/* { dg-require-effective-target lp64 } */
 /* If configured with --enable-standard-branch-protection, don't use
    command line option.  */
 /* { dg-additional-options "-mbranch-protection=standard" { target { ! default_branch_protection } } } */

gcc/testsuite/gcc.target/aarch64/bti-2.c

 /* { dg-do run } */
+/* { dg-require-effective-target lp64 } */
 /* { dg-require-effective-target aarch64_bti_hw } */
 /* If configured with --enable-standard-branch-protection, don't use
    command line option.  */

gcc/testsuite/gcc.target/aarch64/bti-3.c

 /* This is a copy of gcc/testsuite/gcc.c-torture/execute/pr56982.c to test the
    setjmp case of the bti pass.  */
 /* { dg-do run } */
+/* { dg-require-effective-target lp64 } */
 /* { dg-require-effective-target aarch64_bti_hw } */
 /* { dg-options "--save-temps -mbranch-protection=standard" } */