Attempting to load a wallet with an unknown descriptor causes a fatal error:

```
2022-09-06T01:51:06Z init message: Loading wallet…
2022-09-06T01:51:06Z [descriptor] Invalid descriptor: Can only have tr at top level: iostream error
2022-09-06T01:51:06Z [descriptor] Invalid descriptor: Can only have tr at top level: iostream error
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 50e6032b4d1d62c020ebb6a4d0c8fafc6f01ea80f4d2a41c1a256086611636e9, type = legacy, internal = false
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 7f709abbde61e8c253798375692bf41202e625ed74a65f9474d464be34fb2870, type = p2sh-segwit, internal = false
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 2dc6c34099e0ca1235fc990a51042967ecbc8c8ac57062f964739cba2f451be8, type = bech32, internal = false
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 8d3c63ea1ac9936e789713dc8bae857d328ff029ab9392e67c716752e9b11b0c, type = bech32m, internal = false
2022-09-06T01:51:06Z [descriptor] Releasing wallet
2022-09-06T01:51:06Z 

************************
EXCEPTION: St12out_of_range       
map::at       
bitcoin in Runaway exception       



************************
EXCEPTION: St12out_of_range       
map::at       
bitcoin in Runaway exception       

bitcoin-qt: ./checkqueue.h:204: CCheckQueue<CScriptCheck>::~CCheckQueue() [T = CScriptCheck]: Assertion `m_worker_threads.empty()' failed.
Aborted
```

> A fatal error occurred. Bitcoin Core can no longer continue safely and will quit.

To reproduce, a quick hack:

```c++
--- a/src/script/descriptor.cpp
+++ b/src/script/descriptor.cpp
@@ -1408,7 +1408,7 @@ std::unique_ptr<DescriptorImpl> ParseScript(uint32_t& key_exp_index, Span<const
         error = "Can only have addr() at top level";
         return nullptr;
     }
-    if (ctx == ParseScriptContext::TOP && Func("tr", expr)) {
+    if (ctx == ParseScriptContext::TOP && Func("trx", expr)) {
         auto arg = Expr(expr);
         auto internal_key = ParsePubkey(key_exp_index, arg, ParseScriptContext::P2TR, out, error);
         if (!internal_key) {
```
for (auto& desc_spkm  data.desc_spkms) {
        if (m_spk_managers.count(desc_spkm->GetID()) > 0) {
            error = _("Error Duplicate s created during migration. Your  may be corrupted.");
            return false;
        }
        m_spk_managers[desc_spkm->GetID()] = stdmove(desc_spkm);
    }
    // Remove the LegacyScriptPubKeyMan from disk
    if (!legacy_spkm->DeleteRecords()) {
        return false;
    }
    // Remove the LegacyScriptPubKeyMan from memory
    m_spk_managers.erase(legacy_spkm->GetID());
    m_external_spk_managers.clear();
    m_internal_spk_managers.clear();
    // Setup new s
    SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
    if (!IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
        // Use the existing master key if we have it
        if (data.master_key.key.IsValid()) {
            SetupDescriptorScriptPubKeyMans(data.master_key);
        } else {
            // Setup wit
            SetupDescriptorScriptPubKeyMans();
        }
    }
    // Check if the transactions in th are still ours. Either they belong here, or they belong in the wa.
    // We need to go through these in the tx insertion order so that lookups to spends works.
    stdvector<uint256> txids_to_delete;
    for (const auto& [_pos, wtx]  wtxOrdered) {