Revert "Rename all test files from JS -> ES6"

This reverts commit 2abe85b834.

test/javascripts/components/d-button-test.js

@@ -1,56 +0,0 @@
-import componentTest from "helpers/component-test";
-moduleForComponent("d-button", { integration: true });
-
-componentTest("icon only button", {
-  template: '{{d-button icon="plus" tabindex="3"}}',
-
-  test(assert) {
-    assert.ok(
-      find("button.btn.btn-icon.no-text").length,
-      "it has all the classes"
-    );
-    assert.ok(find("button .d-icon.d-icon-plus").length, "it has the icon");
-    assert.equal(find("button").attr("tabindex"), "3", "it has the tabindex");
-  }
-});
-
-componentTest("icon and text button", {
-  template: '{{d-button icon="plus" label="topic.create"}}',
-
-  test(assert) {
-    assert.ok(
-      find("button.btn.btn-icon-text").length,
-      "it has all the classes"
-    );
-    assert.ok(find("button .d-icon.d-icon-plus").length, "it has the icon");
-    assert.ok(find("button span.d-button-label").length, "it has the label");
-  }
-});
-
-componentTest("text only button", {
-  template: '{{d-button label="topic.create"}}',
-
-  test(assert) {
-    assert.ok(find("button.btn.btn-text").length, "it has all the classes");
-    assert.ok(find("button span.d-button-label").length, "it has the label");
-  }
-});
-
-componentTest("form attribute", {
-  template: '{{d-button form="login-form"}}',
-
-  test(assert) {
-    assert.ok(exists("button[form=login-form]"), "it has the form attribute");
-  }
-});
-
-componentTest("link-styled button", {
-  template: '{{d-button display="link"}}',
-
-  test(assert) {
-    assert.ok(
-      find("button.btn-link:not(.btn)").length,
-      "it has the right classes"
-    );
-  }
-});