Remove redundant test

test/CodeGenCXX/debug-info-zero-length-arrays.cpp tests this
functionality more comprehensively

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279444 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGenCXX/debug-info-flex-member.cpp

-// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited -triple x86_64-apple-darwin %s -o - | FileCheck %s
-
-// CHECK: !DISubrange(count: -1)
-
-struct StructName {
-  int member[];
-};
-
-struct StructName SN;