rename instcombine test file. NFC

llvm-svn: 298904

diff --git a/llvm/test/Transforms/InstCombine/phi-select-constexpr.ll b/llvm/test/Transforms/InstCombine/phi-select-constant.ll
similarity index 100%
rename from llvm/test/Transforms/InstCombine/phi-select-constexpr.ll
rename to llvm/test/Transforms/InstCombine/phi-select-constant.ll