Remove date from test case file name. The PR number provides a unique ID already.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176796 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/ARM/2013-03-09-PR15053.ll b/test/CodeGen/ARM/PR15053.ll
similarity index 100%
rename from test/CodeGen/ARM/2013-03-09-PR15053.ll
rename to test/CodeGen/ARM/PR15053.ll