test(ssr): add fixture for computed prop exploding

packages/@lwc/engine-server/src/__tests__/fixtures/wire/errors/throws-on-computed-key/error.txt

@@ -0,0 +1 @@
+get bothDecorated should not be called

packages/@lwc/engine-server/src/__tests__/fixtures/wire/errors/throws-on-computed-key/index.js

@@ -0,0 +1,3 @@
+export const tagName = 'x-wire';
+export { default } from 'x/wire';
+export * from 'x/wire';

packages/@lwc/engine-server/src/__tests__/fixtures/wire/errors/throws-on-computed-key/modules/x/wire/adapter.js

@@ -0,0 +1,13 @@
+export class adapter {
+    constructor(dataCallback) {
+        this.dc = dataCallback;
+    }
+
+    connect() {}
+
+    update(config) {
+        this.dc(config.name);
+    }
+
+    disconnect() {}
+}

packages/@lwc/engine-server/src/__tests__/fixtures/wire/errors/throws-on-computed-key/modules/x/wire/wire.html

@@ -0,0 +1,3 @@
+<template>
+    {exposedSymbol}
+</template>

packages/@lwc/engine-server/src/__tests__/fixtures/wire/errors/throws-on-computed-key/modules/x/wire/wire.js

@@ -0,0 +1,19 @@
+import { LightningElement, wire } from 'lwc';
+import { adapter } from './adapter';
+const sym = Symbol('computed prop');
+
+export default class Wire extends LightningElement {
+    @wire(adapter, { name: 'symbol' })
+    get [sym]() {
+        throw new Error('get bothDecorated should not be called');
+    }
+
+    @wire(adapter, { name: 'symbol' })
+    set [sym](v) {
+        throw new Error('set bothDecorated should not be called');
+    }
+
+    get exposedSymbol() {
+        return this[sym];
+    }
+}