[K/N] Fixed a data race during monolithic caches creation

For per-file caches the data race is still there, but since per-file caches are
only used for incremental compilation, it's ok to leave it as is for now (we cope
with the data race by using a separate folder for each Gradle task).

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/CacheStorage.kt

@@ -14,13 +14,17 @@ internal class CacheStorage(private val generationState: NativeGenerationState)
     private val outputFiles = generationState.outputFiles
 
     companion object {
-        fun renameOutput(outputFiles: OutputFiles) {
-            // For caches the output file is a directory. It might be created by someone else,
-            // we have to delete it in order for the next renaming operation to succeed.
-            val tempDirectoryForRemoval = File(outputFiles.mainFileName + "-to-remove")
-            if (outputFiles.mainFile.exists && !outputFiles.mainFile.renameTo(tempDirectoryForRemoval))
-                return
-            tempDirectoryForRemoval.deleteRecursively()
+        fun renameOutput(outputFiles: OutputFiles, overwrite: Boolean) {
+            if (outputFiles.mainFile.exists) {
+                if (!overwrite)
+                    return
+                // For caches the output file is a directory. It might be already created,
+                // we have to delete it in order for the next renaming operation to succeed.
+                val tempDirectoryForRemoval = File(outputFiles.mainFileName + "-to-remove")
+                if (!outputFiles.mainFile.renameTo(tempDirectoryForRemoval))
+                    return
+                tempDirectoryForRemoval.deleteRecursively()
+            }
             if (!outputFiles.tempCacheDirectory!!.renameTo(outputFiles.mainFile))
                 outputFiles.tempCacheDirectory.deleteRecursively()
         }

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/driver/phases/CacheBuilding.kt

@@ -45,7 +45,7 @@ internal val SaveAdditionalCacheInfoPhase = createSimpleNamedCompilerPhase<Nativ
 internal val FinalizeCachePhase = createSimpleNamedCompilerPhase<PhaseContext, OutputFiles>(
         name = "FinalizeCache",
         description = "Finalize cache (rename temp to the final dist)"
-) { _, outputFiles ->
+) { context, outputFiles ->
     //  TODO: Explicit parameter
-    CacheStorage.renameOutput(outputFiles)
+    CacheStorage.renameOutput(outputFiles, overwrite = context.config.producePerFileCache)
 }