[mips] Remove -allow-deprecated-dag-overlap flag from tests. NFC

Fix DAG check statements in MIPS codegen tests to remove
-allow-deprecated-dag-overlap flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343730 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed