[mips] Move test to correct directory. NFCI

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316081 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/Mips/constMaterialization.ll b/test/CodeGen/Mips/cstmaterialization/constMaterialization.ll
similarity index 100%
rename from test/CodeGen/Mips/constMaterialization.ll
rename to test/CodeGen/Mips/cstmaterialization/constMaterialization.ll