Change allowBackup tests to use qlref test format

Due to some limitations of comments in XML, it is simpler to implement
the `android:allowBackup` tests using the qlref/expectations test format.

Author: egregius313

java/ql/test/query-tests/security/CWE-312/android/backup/AllowBackupEnabledTest.expected

@@ -0,0 +1,2 @@
+| TestExplicitlyEnabled/AndroidManifest.xml:6:5:27:19 | application | The 'android:allowBackup' attribute is enabled. |
+| TestMissing/AndroidManifest.xml:6:5:27:19 | application | The 'android:allowBackup' attribute is enabled. |

java/ql/test/query-tests/security/CWE-312/android/backup/AllowBackupEnabledTest.ql

@@ -0,0 +1 @@
+Security/CWE/CWE-312/AllowBackupAttributeEnabled.ql

java/ql/test/query-tests/security/CWE-312/android/backup/AllowBackupEnabledTest.qlref

@@ -3,7 +3,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="com.example.myapplication">
 
-    <!-- $ hasAllowBackupEnabled --> <application
+    <application
         android:allowBackup="true"
         android:dataExtractionRules="@xml/data_extraction_rules"
         android:fullBackupContent="@xml/backup_rules"

java/ql/test/query-tests/security/CWE-312/android/backup/TestExplicitlyEnabled/AndroidManifest.xml

@@ -3,7 +3,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     package="com.example.myapplication">
 
-    <!-- $ hasAllowBackupEnabled --> <application
+    <application
         android:dataExtractionRules="@xml/data_extraction_rules"
         android:fullBackupContent="@xml/backup_rules"
         android:icon="@mipmap/ic_launcher"

java/ql/test/query-tests/security/CWE-312/android/backup/TestMissing/AndroidManifest.xml

@@ -0,0 +1,2 @@
+// semmle-extractor-options: --javac-args -cp ${testdir}/../../../../../stubs/google-android-9.0.0
+// codeql-extractor-kotlin-options: ${testdir}/../../../../../stubs/google-android-9.0.0