Check also drop-box content in multi-module line marker tests

Related to KT-26957

GitOrigin-RevId: 3e842ee33b5127a917570d943c9f750f648f2004

plugins/kotlin/idea/tests/testData/multiModuleLineMarker/expectEnumEntriesInOneLine/common/common.kt

@@ -1,3 +1,10 @@
 package test
 
-expect enum class <lineMarker>Enum</lineMarker> { A, B, C, D }
+expect enum class <lineMarker descr="Has actuals in JVM">Enum</lineMarker> { A, B, C, D }
+
+/*
+LINEMARKER: Has actuals in JVM
+TARGETS:
+jvm.kt
+actual enum class <5>Enum { <1>A, <2>B, <3>C, <4>D }
+*/