tests: Add avm2/sandbox_type_local_file test

Verifies the sandbox type of a local SWF with network disabled.

tests/tests/swfs/avm2/sandbox_type_local_file/Test.as

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+package {
+    import flash.display.Sprite;
+    import flash.system.Security;
+
+    // Compile with network disabled
+    public class Test extends Sprite {
+        public function Test() {
+            trace("Current sandbox type: " + Security.sandboxType);
+        }
+    }
+}

tests/tests/swfs/avm2/sandbox_type_local_file/output.txt

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+Current sandbox type: localWithFile

tests/tests/swfs/avm2/sandbox_type_local_file/test.toml

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+num_ticks = 1