[test] Speculative fix for r369966 on llvm-clang-x86_64-win

Run the MIR pipeline in this test to completion to try and avoid a "Bad
machine code" error.

Build failure:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190826/688338.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370145 91177308-0d34-0410-b5e6-96231b3b80d8

test/DebugInfo/MIR/X86/DW_OP_entry_value.mir

@@ -1,4 +1,4 @@
-# RUN: llc -debug-entry-values -mtriple=x86_64-apple-darwin -o %t %s -filetype=obj
+# RUN: llc -debug-entry-values -start-before=livedebugvalues -mtriple=x86_64-apple-darwin -o %t %s -filetype=obj
 # RUN: llvm-dwarfdump %t | FileCheck %s
 #
 # int global;