Optimize script definitions handling

Loading script configs only from project root dir
Optimize script definition retrieval in the KtScript

compiler/frontend/src/org/jetbrains/kotlin/psi/KtScript.java

@@ -30,6 +30,19 @@ import java.util.List;
 
 public class KtScript extends KtNamedDeclarationStub<KotlinScriptStub> implements KtDeclarationContainer {
 
+    private KotlinScriptDefinition kotlinScriptDefinitionField = null;
+    private boolean kotlinScriptDefinitionInitialized = false;
+
+    // make it a simple lazy value after converting to kotlin
+    private KotlinScriptDefinition getKotlinScriptDefinition() {
+        if (!kotlinScriptDefinitionInitialized) {
+            kotlinScriptDefinitionField = GetScriptDefinitionKt.getScriptDefinition(getContainingKtFile());
+            kotlinScriptDefinitionInitialized = true;
+            assert kotlinScriptDefinitionField != null : "Should not parse a script without definition";
+        }
+        return kotlinScriptDefinitionField;
+    }
+
     public KtScript(@NotNull ASTNode node) {
         super(node);
     }
@@ -46,10 +59,7 @@ public class KtScript extends KtNamedDeclarationStub<KotlinScriptStub> implement
             return stub.getFqName();
         }
         KtFile containingKtFile = getContainingKtFile();
-        KotlinScriptDefinition kotlinScriptDefinition =
-                GetScriptDefinitionKt.getScriptDefinition(containingKtFile);
-        assert kotlinScriptDefinition != null : "Should not parse a script without definition";
-        return containingKtFile.getPackageFqName().child(kotlinScriptDefinition.getScriptName(this));
+        return containingKtFile.getPackageFqName().child(getKotlinScriptDefinition().getScriptName(this));
     }
 
     @Override

compiler/frontend/src/org/jetbrains/kotlin/script/scriptConfig.kt

@@ -36,8 +36,8 @@ fun isScriptDefinitionConfigFile(file: java.io.File) = file.isFile && file.name.
 fun isScriptDefinitionConfigFile(file: com.intellij.openapi.vfs.VirtualFile) = !file.isDirectory && file.name.endsWith(org.jetbrains.kotlin.script.SCRIPT_CONFIG_FILE_EXTENSION)
 
 fun loadScriptConfigsFromProjectRoot(projectRoot: java.io.File): List<org.jetbrains.kotlin.script.KotlinScriptConfig> =
-        projectRoot.walk().filter(::isScriptDefinitionConfigFile).toList()
-                .flatMap { loadScriptConfigs(it) }
+        projectRoot.listFiles { it -> isScriptDefinitionConfigFile(it) }.toList()
+            .flatMap { loadScriptConfigs(it) }
 
 fun loadScriptConfigs(configFile: File): List<KotlinScriptConfig> =
         JDOMUtil.loadDocument(configFile).rootElement.children.mapNotNull {