[PrepareForEmission] Crash when inout operations are passed to instance ports

Nobody has claimed this yet.

```mlir
hw.module @TopXMRAsserts(%I: !hw.inout) -> () {}
hw.module @Top() -> () {
%I = sv.wire : !hw.inout
hw.instance "TopXMRAsserts_inst0" sym @Top.TopXMRAsserts_inst0 @TopXMRAsserts(I: %I: !hw.inout) -> () {doNotPrint = 1}
}
sv.bind #hw.innerNameRef<@Top::@Top.TopXMRAsserts_inst0>
```
`circt-opt -export-verilog`:
```
circt-opt: /home/uenoku/dev/circt/llvm/llvm/../mlir/include/mlir/IR/StorageUniquerSupport.h:153: static ConcreteT mlir::detail::StorageUserBase::get(mlir::MLIRContext *, Args...) [ConcreteT = circt::hw::InOutType, BaseT = mlir::Type, StorageT = circt::hw::detail::InOutTypeStorage, UniquerT = mlir::detail::TypeUniquer, Traits = <>, Args = ]: Assertion `succeeded(ConcreteT::verify(getDefaultDiagnosticEmitFn(ctx), args...))' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
#0 0x000055ccf68fee23 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/uenoku/dev/circt/llvm/llvm/lib/Support/Unix/Signals.inc:569:13
#1 0x000055ccf68fd0e0 llvm::sys::RunSignalHandlers() /home/uenoku/dev/circt/llvm/llvm/lib/Support/Signals.cpp:104:18
#2 0x000055ccf68ff47a SignalHandler(int) /home/uenoku/dev/circt/llvm/llvm/lib/Support/Unix/Signals.inc:407:1
#3 0x00007f04f0242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x00007f04f0296a7c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
#5 0x00007f04f0296a7c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
#6 0x00007f04f0296a7c pthread_kill ./nptl/pthread_kill.c:89:10
#7 0x00007f04f0242476 gsignal ./signal/../sysdeps/posix/raise.c:27:6
#8 0x00007f04f02287f3 abort ./stdlib/abort.c:81:7
#9 0x00007f04f022871b _nl_load_domain ./intl/loadmsgcat.c:1177:9
#10 0x00007f04f0239e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#11 0x000055ccf6eb5897 (./bin/circt-opt+0xb1b897)
#12 0x000055ccf6fd56e8 circt::sv::WireOp::build(mlir::OpBuilder&, mlir::OperationState&, mlir::Type, mlir::StringAttr, mlir::StringAttr) /home/uenoku/dev/circt/lib/Dialect/SV/SVOps.cpp:1296:21
#13 0x000055ccf6ffd651 circt::sv::WireOp::build(mlir::OpBuilder&, mlir::OperationState&, mlir::Type, llvm::StringRef) /home/uenoku/dev/circt/build/tools/circt/include/circt/Dialect/SV/SV.cpp.inc:15061:7
#14 0x000055ccf6a68d51 circt::sv::WireOp mlir::OpBuilder::create&>(mlir::Location, mlir::Type&&, llvm::SmallString<32u>&) /home/uenoku/dev/circt/llvm/llvm/../mlir/include/mlir/IR/Builders.h:460:16
#15 0x000055ccf6a658ac spillWiresForInstanceInputs(circt::hw::InstanceOp) /home/uenoku/dev/circt/lib/Conversion/ExportVerilog/PrepareForEmission.cpp:103:28
#16 0x000055ccf6a658ac legalizeHWModule(mlir::Block&, circt::LoweringOptions const&) /home/uenoku/dev/circt/lib/Conversion/ExportVerilog/PrepareForEmission.cpp:735:9
```

Start with the reproducer and run `circt-opt -export-verilog` to confirm the crash. Read `lib/Conversion/ExportVerilog/PrepareForEmission.cpp`, especially `spillWiresForInstanceInputs` and `legalizeHWModule`, along with the `sv::WireOp::build` stack entry; done means the inout instance-port input is handled without the assertion failure.

Written by the indexing model from the issue text.