gradle-plugin, tests: Create directories in the 'createFile' method

tools/kotlin-native-gradle-plugin/src/test/groovy/org/jetbrains/kotlin/gradle/plugin/test/IncrementalSpecification.groovy

@@ -119,7 +119,6 @@ class IncrementalSpecification extends BaseKonanSpecification {
         when:
         def project = KonanInteropProject.createEmpty(projectDirectory) { KonanInteropProject it ->
             it.generateSrcFile('main.kt')
-            it.createSubDir('src', 'foo', 'kotlin')
             it.generateSrcFile(["src", "foo", "kotlin"], 'bar.kt', """
                 fun main(args: Array<String>) { println("Hello!") }
             """.stripIndent())
@@ -137,7 +136,6 @@ class IncrementalSpecification extends BaseKonanSpecification {
         when:
         def project = KonanInteropProject.createEmpty(projectDirectory) { KonanInteropProject it ->
             it.generateSrcFile('main.kt')
-            it.createSubDir('src', 'lib', 'kotlin')
             it.generateSrcFile(["src", "lib", "kotlin"], "lib.kt", "fun bar() { println(\"Hello!\") }")
             it.buildFile.append("""
                 konanArtifacts {
@@ -254,7 +252,6 @@ class IncrementalSpecification extends BaseKonanSpecification {
         when:
         def project = KonanInteropProject.createEmpty(projectDirectory) { KonanInteropProject it ->
             it.generateSrcFile('main.kt')
-            it.createSubDir('src', 'lib', 'kotlin')
             it.generateSrcFile(["src", "lib", "kotlin"], 'lib.kt', 'fun foo() { println(42) }')
             it.buildFile.append("""
                 konanArtifacts {

tools/kotlin-native-gradle-plugin/src/test/groovy/org/jetbrains/kotlin/gradle/plugin/test/KonanProject.groovy

@@ -59,7 +59,9 @@ class KonanProject {
 
     /** Creates a file with the given content in project subdirectory specified by parentDirectory. */
     File createFile(Path parentDirectory = projectPath, String fileName, String content) {
-        def result = projectPath.resolve(parentDirectory).resolve(fileName).toFile()
+        def parent = projectPath.resolve(parentDirectory)
+        Files.createDirectories(parent)
+        def result = parent.resolve(fileName).toFile()
         result.createNewFile()
         result.write(content)
         return result
@@ -304,7 +306,7 @@ class KonanInteropProject extends KonanProject {
         return result
     }
 
-    /** Creates a project with the default build file and without any source or def files. */
+    /** Creates a project with the default build file, without any source and with an empty def file. */
     static KonanInteropProject createEmpty(File projectDir) {
         def result = new KonanInteropProject(projectDir)
         result.with {
@@ -316,7 +318,7 @@ class KonanInteropProject extends KonanProject {
         return result
     }
 
-    /** Creates a project with the default build file and without any source or def files. */
+    /** Creates a project with the default build file, without any source and with an empty def file. */
     static KonanInteropProject createEmpty(File projectDir, Closure config) {
         def result = createEmpty(projectDir)
         config(result)