[Low Level FIR] fix CME in java enhancement

Now all computations in FirThreadSafeCache are performed under lock

^KTIJ-23081 fixed

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/caches/NullValue.kt

@@ -19,6 +19,6 @@ internal inline fun <KEY : Any, RESULT> ConcurrentMap<KEY, Any>.getOrPutWithNull
     key: KEY,
     crossinline compute: (KEY) -> Any?
 ): RESULT {
-    val value = getOrPut(key) { compute(key) ?: NullValue }
+    val value = computeIfAbsent(key) { compute(key) ?: NullValue }
     return value.nullValueToNull()
 }