[LL API] Fix on-air analysis for scripts (KTIJ-21108)

The implementation is rather limited. Advanced cases, such as
replacing a script with another one with different import directives,
won't work because of non-trivial relationship between 'FirFile' and
'FirScript'.

compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -1049,7 +1049,11 @@ open class RawFirBuilder(
                     declarations += when (declaration) {
                         is KtScript -> {
                             require(file.declarations.size == 1) { "Expect the script to be the only declaration in the file $name" }
-                            convertScript(declaration, this)
+                            convertScript(declaration, this.name) {
+                                for (configurator in baseSession.extensionService.scriptConfigurators) {
+                                    with(configurator) { configure(this@buildFile) }
+                                }
+                            }
                         }
                         is KtDestructuringDeclaration -> buildErrorTopLevelDestructuringDeclaration(declaration.toFirSourceElement())
                         else -> declaration.convert()
@@ -1062,12 +1066,12 @@ open class RawFirBuilder(
             }
         }
 
-        private fun convertScript(script: KtScript, containingFile: FirFileBuilder): FirScript {
+        private fun convertScript(script: KtScript, fileName: String, setup: FirScriptBuilder.() -> Unit = {}): FirScript {
             return buildScript {
                 source = script.toFirSourceElement()
                 moduleData = baseModuleData
                 origin = FirDeclarationOrigin.Source
-                name = Name.special("<script-${containingFile.name}>")
+                name = Name.special("<script-$fileName>")
                 symbol = FirScriptSymbol(context.packageFqName.child(name))
                 for (declaration in script.declarations) {
                     when (declaration) {
@@ -1079,12 +1083,13 @@ open class RawFirBuilder(
                         }
                     }
                 }
-                baseSession.extensionService.scriptConfigurators.forEach { with(it) { configure(containingFile) } }
+                setup()
             }
         }
 
         override fun visitScript(script: KtScript, data: Unit?): FirElement {
-            error("should not be here")
+            val fileName = script.containingKtFile.name
+            return convertScript(script, fileName)
         }
 
         protected fun KtEnumEntry.toFirEnumEntry(

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/builder/FirScriptBuilder.kt

@@ -70,3 +70,23 @@ inline fun buildScript(init: FirScriptBuilder.() -> Unit): FirScript {
     }
     return FirScriptBuilder().apply(init).build()
 }
+
+@OptIn(ExperimentalContracts::class)
+inline fun buildScriptCopy(original: FirScript, init: FirScriptBuilder.() -> Unit): FirScript {
+    contract {
+        callsInPlace(init, kotlin.contracts.InvocationKind.EXACTLY_ONCE)
+    }
+    val copyBuilder = FirScriptBuilder()
+    copyBuilder.source = original.source
+    copyBuilder.resolvePhase = original.resolvePhase
+    copyBuilder.annotations.addAll(original.annotations)
+    copyBuilder.moduleData = original.moduleData
+    copyBuilder.origin = original.origin
+    copyBuilder.attributes = original.attributes.copy()
+    copyBuilder.name = original.name
+    copyBuilder.statements.addAll(original.statements)
+    copyBuilder.symbol = original.symbol
+    copyBuilder.parameters.addAll(original.parameters)
+    copyBuilder.contextReceivers.addAll(original.contextReceivers)
+    return copyBuilder.apply(init).build()
+}

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/BuilderConfigurator.kt

@@ -357,6 +357,10 @@ object BuilderConfigurator : AbstractBuilderConfigurator<FirTreeBuilder>(FirTree
             fields from resolvedQualifier
         }
 
+        builder(script) {
+            withCopy()
+        }
+
         builder(resolvedQualifier) {
             parents += abstractResolvedQualifierBuilder
             defaultFalse("isNullableLHSForCallableReference", "isFullyQualified")