Move .mir tests to appropriate directories

test/CodeGen/MIR should contain tests that intent to test the MIR
printing or parsing. Tests that test something else should be in
test/CodeGen/TargetName even when they are written in .mir.

As a rule of thumb, only tests using "llc -run-pass none" should be in
test/CodeGen/MIR.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289254 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/MIR/Lanai/lit.local.cfg

@@ -1,2 +0,0 @@
-if not 'Lanai' in config.root.targets:
-    config.unsupported = True