Don't create build directory for task in getter

Since the property is public, it can be invoked from outside,
possibly trough other properties.
This can lead to unwanted side effects: we can create taskBuildDirectory,
because some other task reads the property in parallel with 'clean' task
in current project.
That's exactly what happened when we referenced the property from
'GradleCompilerRunner#buildModulesInfo'.

    #KT-24938 fixed

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt

@@ -111,9 +111,10 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractKo
         cacheOnlyIfEnabledForKotlin()
     }
 
+    // avoid creating directory in getter: this can lead to failure in parallel build
     @get:LocalState
     internal val taskBuildDirectory: File
-        get() = File(File(project.buildDir, KOTLIN_BUILD_DIR_NAME), name).apply { mkdirs() }
+        get() = File(File(project.buildDir, KOTLIN_BUILD_DIR_NAME), name)
 
     // indicates that task should compile kotlin incrementally if possible
     // it's not possible when IncrementalTaskInputs#isIncremental returns false (i.e first build)
@@ -249,6 +250,7 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractKo
 
         sourceRoots.log(this.name, logger)
         val args = prepareCompilerArguments()
+        taskBuildDirectory.mkdirs()
         callCompiler(args, sourceRoots, ChangedFiles(inputs))
     }