fix: menu compatibility with IE (node type statement) (vuematerial#1365)

* fix: compare node by type

dom constructors do not have name property in IE.
replace that with comparing by their node type.

fix vuematerial#1263

* fix(MdMenuContent): height for IE

got height `0` with style `flex-direction: column`

fix vuematerial#1263

Author: VdustR

src/components/MdMenu/MdMenuContent.vue

@@ -248,7 +248,7 @@
     max-width: $md-menu-base-width * 5;
     max-height: 35vh;
     display: flex;
-    flex-direction: column;
+    flex-direction: row;
     position: absolute;
     z-index: 60;
     border-radius: 2px;

src/components/MdPopover/MdPopover.vue

@@ -91,7 +91,7 @@
         if (this.mdSettings) {
           const options = deepmerge(this.getPopperOptions(), this.mdSettings)
 
-          if (this.$el.constructor.name.toLowerCase() !== 'comment') {
+          if (this.$el.nodeType !== Node.COMMENT_NODE) {
             this.popperInstance = new Popper(this.originalParentEl, this.$el, options)
           }
         }

src/components/MdPortal/MdPortal.js

@@ -98,7 +98,7 @@ export default {
     async initDestroy (manualCall) {
       let el = this.$el
 
-      if (manualCall && this.$el.constructor.name.toLowerCase() === 'comment') {
+      if (manualCall && this.$el.nodeType === Node.COMMENT_NODE) {
         el = this.$vnode.elm
       }