Do not call pop_back when app has no uses-sdk

Calling pop_back on an empty container results in undefined behavior.
aapt2 dump badging seg faults when used on an APK with no uses-sdk.

Bug: 188461703
Test: aapt2 dump badging HelloAppTest.apk
Change-Id: I8d8308a06d542f003ae399629bdbfb5b845674fc
diff --git a/tools/aapt2/dump/DumpManifest.cpp b/tools/aapt2/dump/DumpManifest.cpp
index f2c6b15..9574d27 100644
--- a/tools/aapt2/dump/DumpManifest.cpp
+++ b/tools/aapt2/dump/DumpManifest.cpp
@@ -1978,12 +1978,13 @@
       filtered_uses_sdk_tags.emplace_back(uses_sdk);
     }
   }
-  filtered_uses_sdk_tags.pop_back();
-
-  root->Filter([&](const ManifestExtractor::Element* e) {
-    return std::find(filtered_uses_sdk_tags.begin(), filtered_uses_sdk_tags.end(), e) !=
-           filtered_uses_sdk_tags.end();
-  });
+  if (filtered_uses_sdk_tags.size() >= 2U) {
+    filtered_uses_sdk_tags.pop_back();
+    root->Filter([&](const ManifestExtractor::Element* e) {
+      return std::find(filtered_uses_sdk_tags.begin(), filtered_uses_sdk_tags.end(), e) !=
+             filtered_uses_sdk_tags.end();
+    });
+  }
 
   // Print the elements in order seen
   Print(root.get(), printer);