x86/cet: fix shadow stack test scripts

Some shadow stack test scripts use the '==' operator with the 'test'
command to validate exit codes resulting in the following error:

  sysdeps/x86_64/tst-shstk-legacy-1e.sh: 31: test: 139: unexpected operator

The '==' operator is invalid for the 'test' command, use '-eq' like the
previous call to 'test'.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 155bb9d036)

sysdeps/x86_64/tst-shstk-legacy-1e-static.sh

@@ -26,7 +26,7 @@ ${common_objpfx}elf/tst-shstk-legacy-1e-static
 status=$?
 if test $status -eq 77; then
   exit 77
-elif test $status == 139; then
+elif test $status -eq 139; then
   exit 0
 else
   exit 1

sysdeps/x86_64/tst-shstk-legacy-1e.sh

@@ -28,7 +28,7 @@ ${test_program_prefix} \
 status=$?
 if test $status -eq 77; then
   exit 77
-elif test $status == 139; then
+elif test $status -eq 139; then
   exit 0
 else
   exit 1

sysdeps/x86_64/tst-shstk-legacy-1g.sh

@@ -28,7 +28,7 @@ ${test_program_prefix} \
 status=$?
 if test $status -eq 77; then
   exit 77
-elif test $status == 139; then
+elif test $status -eq 139; then
   exit 0
 else
   exit 1