Add use-directory-name test

This test case checks whether the "meaninglessFileNames" option is
applied properly to the "code.js" file and its parent directory name is
being used instead of its file name.

test/fixtures/use-directory-name/.babelrc

@@ -0,0 +1,12 @@
+{
+  "plugins": [
+    [
+      "../../../src",
+      {
+        "meaninglessFileNames": ["code"],
+        "transpileTemplateLiterals": false,
+        "ssr": true
+      }
+    ]
+  ]
+}

test/fixtures/use-directory-name/code.js

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+import styled from "styled-components";
+
+const Test = styled.div`color: red;`;
+const before = styled.div`color: blue;`;
+styled.div``;
+export default styled.button``;

test/fixtures/use-directory-name/output.js

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+import styled from "styled-components";
+const Test = styled.div.withConfig({
+  displayName: "use-directory-name__Test",
+  componentId: "sc-193y009-0"
+})`color:red;`;
+const before = styled.div.withConfig({
+  displayName: "use-directory-name__before",
+  componentId: "sc-193y009-1"
+})`color:blue;`;
+styled.div.withConfig({
+  displayName: "use-directory-name",
+  componentId: "sc-193y009-2"
+})``;
+export default styled.button.withConfig({
+  displayName: "use-directory-name",
+  componentId: "sc-193y009-3"
+})``;