[wip] fix prop normalization

This (along with some changes to Ember that I will also PR) solves emberjs/ember.js#16311 and emberjs/ember.js#16477

This is not ready to go yet because I'm also going to refactor so we don't compute the normalized property name twice.

packages/@glimmer/runtime/lib/vm/attributes/dynamic.ts

@@ -81,20 +81,27 @@ export class SimpleDynamicAttribute extends DynamicAttribute {
 }
 
 export class DefaultDynamicProperty extends DynamicAttribute {
+  private normalizedName: string;
+
+  constructor(attribute: Attribute) {
+    super(attribute);
+    let { element, name } = this.attribute;
+    this.normalizedName = normalizeProperty(element, name).normalized;
+  }
+
   value: Opaque;
   set(dom: ElementBuilder, value: Opaque, _env: Environment): void {
     if (value !== null && value !== undefined) {
-      let { name } = this.attribute;
       this.value = value;
-      dom.__setProperty(name, value);
+      dom.__setProperty(this.normalizedName, value);
     }
   }
 
   update(value: Opaque, _env: Environment): void {
-    let { element, name } = this.attribute;
+    let { element } = this.attribute;
 
     if (this.value !== value) {
-      element[name] = this.value = value;
+      element[this.normalizedName] = this.value = value;
 
       if (value === null || value === undefined) {
         this.removeAttribute();
@@ -106,12 +113,12 @@ export class DefaultDynamicProperty extends DynamicAttribute {
   protected removeAttribute() {
     // TODO this sucks but to preserve properties first and to meet current
     // semantics we must do this.
-    let { element, name, namespace } = this.attribute;
+    let { element, namespace } = this.attribute;
 
     if (namespace) {
-      element.removeAttributeNS(namespace, name);
+      element.removeAttributeNS(namespace, this.normalizedName);
     } else {
-      element.removeAttribute(name);
+      element.removeAttribute(this.normalizedName);
     }
   }
 }