[X86] Fix a test from r357317

Summary:
The missing `<` causes the lld command to override the test file, which fails in
environments marking the test files as readonly.

Reviewers: bkramer

Reviewed By: bkramer

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60060

llvm-svn: 357380