Temporary fix to avoid runtime exception due to incorrect inferred type

Caused by: java.lang.ClassCastException:
kotlin.collections.EmptySet cannot be cast to java.lang.Void
  at org.jetbrains.kotlin.codegen.coroutines.CoroutineTransformerMethodVisitorKt.findSafelyReachableReturns(CoroutineTransformerMethodVisitor.kt:984)

Co-authored-by: Alexander Udalov <alexander.udalov@jetbrains.com>

compiler/backend/src/org/jetbrains/kotlin/codegen/coroutines/CoroutineTransformerMethodVisitor.kt

@@ -982,7 +982,7 @@ private fun findSafelyReachableReturns(methodNode: MethodNode, sourceFrames: Arr
         if (!insn.isMeaningful || insn.opcode in SAFE_OPCODES || insn.isInvisibleInDebugVarInsn(methodNode) ||
             isInlineMarker(insn)) {
             setOf()
-        } else null
+        } else null as Set<Int>?
     }
 
     var changed: Boolean