Fix custom script definition cashing and script validity check:

- reorder initialization logic, so that script definitions are
  requested only after plugins loading
- clear definitions cache after adding explicit definitions or sources

#KT-32206 fixed
#KT-32169 fixed

Note: any of these modification fix the problem alone, but the second
may prevent other similar problems, while the first fixes actual logic
of the script validity checks as well.

plugins/scripting/scripting-compiler/src/org/jetbrains/kotlin/scripting/compiler/plugin/JvmCliScriptEvaluationExtension.kt

@@ -40,6 +40,12 @@ class JvmCliScriptEvaluationExtension : ScriptEvaluationExtension {
             return COMPILATION_ERROR
         }
         val sourcePath = arguments.freeArgs.first()
+
+        configuration.addKotlinSourceRoot(sourcePath)
+        configuration.put(JVMConfigurationKeys.RETAIN_OUTPUT_IN_MEMORY, true)
+        val coreEnvironment =
+            KotlinCoreEnvironment.createForProduction(projectEnvironment, configuration, EnvironmentConfigFiles.JVM_CONFIG_FILES)
+
         val scriptFile = File(sourcePath)
         if (scriptFile.isDirectory || !scriptDefinitionProvider.isScript(scriptFile.name)) {
             val extensionHint =
@@ -48,14 +54,9 @@ class JvmCliScriptEvaluationExtension : ScriptEvaluationExtension {
             messageCollector.report(ERROR, "Specify path to the script file$extensionHint as the first argument")
             return COMPILATION_ERROR
         }
-        configuration.addKotlinSourceRoot(sourcePath)
-        configuration.put(JVMConfigurationKeys.RETAIN_OUTPUT_IN_MEMORY, true)
 
         val scriptArgs = arguments.freeArgs.subList(1, arguments.freeArgs.size)
 
-        val coreEnvironment =
-            KotlinCoreEnvironment.createForProduction(projectEnvironment, configuration, EnvironmentConfigFiles.JVM_CONFIG_FILES)
-
         return KotlinToJVMBytecodeCompiler.compileAndExecuteScript(coreEnvironment, scriptArgs)
     }
 }

plugins/scripting/scripting-compiler/src/org/jetbrains/kotlin/scripting/compiler/plugin/definitions/CliScriptDefinitionProvider.kt

@@ -28,6 +28,7 @@ open class CliScriptDefinitionProvider : LazyScriptDefinitionProvider() {
             definitions.addAll(withoutStdDef)
             // TODO: consider reporting an error when several default definitions are supplied
             defaultDefinition = stdDef.firstOrNull()
+            clearCache()
         }
     }
 
@@ -37,6 +38,7 @@ open class CliScriptDefinitionProvider : LazyScriptDefinitionProvider() {
             for (it in newSources) {
                 definitionsFromSources.add(it.definitions.constrainOnce())
             }
+            clearCache()
         }
     }