Fix test compile errors after LLVM rebase

After the new rebase of Clang, we now support the alloc_size attribute,
so we can remove the warning about switching to alloc_size once Clang
has support.

Also fix an issue where 'false' is returned in a main method.

Test: make cts
Bug: 37752547
Change-Id: I32ee814aaa0338567cb8174a68d7ee1bfece2f75
diff --git a/tests/libs/bionic_tests_zipalign.cpp b/tests/libs/bionic_tests_zipalign.cpp
index 8e31474..56183ba 100644
--- a/tests/libs/bionic_tests_zipalign.cpp
+++ b/tests/libs/bionic_tests_zipalign.cpp
@@ -142,7 +142,7 @@
   if (return_value != 0) {
     CloseArchive(handle);
     fprintf(stderr, "Unable to open '%s': %s\n", argv[2], ErrorCodeString(return_value));
-    return false;
+    return 1;
   }
 
   FILE* zip_dst = fopen(argv[3], "we");