Refactor fc_sort and add unit tests

Clean up fc_sort to facilitate the migration to Python3. Use PEP8 for
naming scheme.

Test: atest --host fc_sort_test
Bug: 200119288
Change-Id: Ia2c40a850a48ec75e995d5233b5abaae10917a89
diff --git a/tests/Android.bp b/tests/Android.bp
index 6a86188..58d4c4f 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -28,7 +28,6 @@
     name: "py2_only",
     version: {
         py2: {
-            embedded_launcher: true,
             enabled: true,
         },
         py3: {
@@ -88,6 +87,18 @@
     defaults: ["py2_only"],
 }
 
+python_test_host {
+    name: "fc_sort_test",
+    srcs: [
+        "fc_sort.py",
+        "fc_sort_test.py",
+    ],
+    defaults: ["py2_only"],
+    test_options: {
+        unit_test: true,
+    }
+}
+
 python_binary_host {
     name: "check_prop_prefix",
     srcs: ["check_prop_prefix.py"],