valgrind: update the ptest subdirs list

Split the list into one directory per line.
Sort the list alphabetically.
Add the gdbserver_tests directory to get the 'gone' executable
which is needed by:
    memcheck/tests/gone_abrt_xml.vgtest

(From OE-Core rev: eb7d907deb09f2658f69d8faa8e56e6a56510fca)

Signed-off-by: Randy MacLeod <Randy.MacLeod@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/valgrind/valgrind_3.15.0.bb

@@ -136,7 +136,17 @@ do_install_ptest() {
         # exclude shell or the package won't install
         rm -rf none/tests/shell* 2>/dev/null
 
-        subdirs="tests cachegrind/tests callgrind/tests drd/tests helgrind/tests massif/tests memcheck/tests none/tests"
+        subdirs=" \
+	   cachegrind/tests \
+	   callgrind/tests \
+	   drd/tests \
+	   gdbserver_tests \
+	   helgrind/tests \
+	   massif/tests \
+	   memcheck/tests \
+	   none/tests \
+	   tests \
+	"
 
         # Get the vg test scripts, filters, and expected files
         for dir in $subdirs ; do