[Test] Use DUMP_EXTERNAL_CLASS instead of invalid DUMP_DEPENDENCIES directive in ir text tests

compiler/testData/ir/irText/stubs/javaSyntheticProperty.kt

@@ -1,10 +1,10 @@
 // TARGET_BACKEND: JVM
 // FIR_IDENTICAL
-// !DUMP_DEPENDENCIES
+// DUMP_EXTERNAL_CLASS: J
 // FILE: javaSyntheticProperty.kt
 val test = J().foo
 
 // FILE: J.java
 class J {
     public String getFoo() { return null; }
-}
+}