[JS] Replace J2V8 based ScriptEngine with a process-based version

The main advantage of this is that we can use a newer and official build of V8.
Also, with new infra, we can use other JS engines.

Other changes:
 * ScriptEngine API is simplified and documented.
 * Introduce ScriptEngineWithTypedResult with typed `eval`, mostly for JsReplEvaluator and JsScriptEvaluator.
 * J2V8 version is completely removed.
 * Use new ScriptEngineV8 everywhere by default.
 * System property `kotlin.js.useNashorn` switches to Nashorn in all tests.

libraries/scripting/js/src/org/jetbrains/kotlin/scripting/repl/js/JsReplEvaluator.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -21,7 +21,7 @@ class JsReplEvaluator : ReplEvaluator {
     ): ReplEvalResult {
         return try {
             val evaluationState = state.asState(JsEvaluationState::class.java)
-            val evalResult = evaluationState.engine.eval<Any?>(compileResult.data as String)
+            val evalResult = evaluationState.engine.evalWithTypedResult<Any?>(compileResult.data as String)
             ReplEvalResult.ValueResult("result", evalResult, "Any?")
         } catch (e: Exception) {
             ReplEvalResult.Error.Runtime("Error while evaluating", e)

libraries/scripting/js/src/org/jetbrains/kotlin/scripting/repl/js/JsReplUtils.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -9,7 +9,7 @@ import org.jetbrains.kotlin.cli.common.repl.*
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.ScriptDescriptor
 import org.jetbrains.kotlin.ir.backend.js.utils.NameTables
-import org.jetbrains.kotlin.js.engine.ScriptEngine
+import org.jetbrains.kotlin.js.engine.ScriptEngineWithTypedResult
 import java.util.concurrent.locks.ReentrantReadWriteLock
 import kotlin.reflect.KClass
 import kotlin.script.experimental.api.CompiledScript
@@ -31,9 +31,9 @@ abstract class JsCompilationState(
     val nameTables: NameTables,
     val dependencies: List<ModuleDescriptor>) : JsState(lock)
 
-class JsEvaluationState(lock: ReentrantReadWriteLock, val engine: ScriptEngine) : JsState(lock) {
+class JsEvaluationState(lock: ReentrantReadWriteLock, val engine: ScriptEngineWithTypedResult) : JsState(lock) {
     override fun dispose() {
-        engine.release()
+        engine.reset()
     }
 }
 

libraries/scripting/js/src/org/jetbrains/kotlin/scripting/repl/js/JsScriptEvaluator.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -17,7 +17,7 @@ class JsScriptEvaluator : ScriptEvaluator {
         scriptEvaluationConfiguration: ScriptEvaluationConfiguration
     ): ResultWithDiagnostics<EvaluationResult> {
         return try {
-            val evalResult = engine.eval<Any?>((compiledScript as JsCompiledScript).jsCode)
+            val evalResult = engine.evalWithTypedResult<Any?>((compiledScript as JsCompiledScript).jsCode)
             ResultWithDiagnostics.Success(
                 EvaluationResult(
                     ResultValue.Value(