Fixing segfault crash in x86_64 get_size testcase am: 11c0034821 am: 34dab56946 am: a4a8a3545c

Original change: https://android-review.googlesource.com/c/platform/external/linux-kselftest/+/1670302

Change-Id: If363074c9f33a60bde60050f06ec667bcb36cd49
diff --git a/Android.bp b/Android.bp
index 71975a4..e56904c 100644
--- a/Android.bp
+++ b/Android.bp
@@ -474,6 +474,11 @@
     name: "kselftest_size_test",
     relative_install_path: "linux-kselftest/size",
     srcs: ["tools/testing/selftests/size/get_size.c"],
+    arch: {
+       x86_64: {
+           cflags: ["-mstackrealign"],
+       },
+    },
     defaults: ["kselftest_defaults"],
     nocrt: true,
     // coverage runtime calls atexit, which is unavailable with nocrt.