[FIRRTL] Don't Clone in ModuleInliner Unless Necessary

Nobody has claimed this yet.

Change FIRRTL Dialect's `ModuleInliner` pass to not clone operations when a move is sufficient. Currently, the `ModuleInliner` works by copying operations and then garbage collecting dead modules.

Consider the following circuit where `Bar` is going to be inlined into `Foo`:

```mlir
firrtl.circuit "Foo" {
firrtl.module @Bar() attributes {annotations = [{class = "firrtl.passes.InlineAnnotation"}]} {
%w = firrtl.wire : !firrtl.uint<1>
}
firrtl.module @Foo() {
firrtl.instance bar @Bar()
}
}
```

This performs one clone of `%w = firrtl.wire` even though a move would suffice. You can see the single clone happen with the following patch:

```diff
diff --git a/lib/Dialect/FIRRTL/Transforms/ModuleInliner.cpp b/lib/Dialect/FIRRTL/Transforms/ModuleInliner.cpp
index a6f6d16a..9fe9935c 100644
--- a/lib/Dialect/FIRRTL/Transforms/ModuleInliner.cpp
+++ b/lib/Dialect/FIRRTL/Transforms/ModuleInliner.cpp
@@ -598,6 +598,7 @@ void Inliner::cloneAndRename(
}

// Clone and rename.
+ llvm::errs() << "// Cloning: " << op << "\n";
auto *newOp = b.clone(op, mapper);
rename(prefix, newOp, moduleNamespace);

```

Running this then produces (circt-opt Foo.mlir -pass-pipeline='firrtl.circuit(firrtl-inliner)':
```mlir
// Cloning: %w = firrtl.wire : !firrtl.uint<1>
module {
firrtl.circuit "Foo" {
firrtl.module @Foo() {
%bar_w = firrtl.wire : !firrtl.uint<1>
}
}
}
```

This issue is based off a @darthscsi comment: https://github.com/llvm/circt/pull/2544#discussion_r799642682.

Start in lib/Dialect/FIRRTL/Transforms/ModuleInliner.cpp, especially Inliner::cloneAndRename, and inspect the firrtl-inliner pass behavior using the circuit example in the issue. Run circt-opt Foo.mlir with -pass-pipeline='firrtl.circuit(firrtl-inliner)' and verify that operations are moved when cloning is unnecessary while the output remains correct.

Written by the indexing model from the issue text.