JVM_IR: refine the condition for mangling names of multifile members

Private $$forInline versions of public suspend functions should not
be mangled. (Note that there are no $$forInline versions of private
suspend functions, as those are effectively inline-only.)

compiler/testData/codegen/boxInline/suspend/inlineSuspendInMultifileClass.kt

@@ -0,0 +1,34 @@
+// FILE: test.kt
+// WITH_RUNTIME
+// WITH_COROUTINES
+// NO_CHECK_LAMBDA_INLINING
+// TARGET_BACKEND: JVM
+// !INHERIT_MULTIFILE_PARTS
+
+// The lambda in box() attempts to store the result in a null Ref for some reason.
+// IGNORE_BACKEND: JVM
+// IGNORE_BACKEND_MULTI_MODULE: JVM
+
+@file:JvmMultifileClass
+@file:JvmName("XKt")
+
+suspend fun suspendHere() {}
+
+suspend inline fun test(c: suspend () -> String): String {
+    suspendHere()
+    val result = c()
+    suspendHere()
+    return result
+}
+
+// FILE: box.kt
+import kotlin.coroutines.*
+import helpers.*
+
+fun box() : String {
+    var res = "fail"
+    suspend {
+        res = test { "OK" }
+    }.startCoroutine(EmptyContinuation)
+    return res
+}