Revert "Build: enable -Werror in stdlib/core/compiler/plugins modules"

This reverts commit 3be62dfc

compiler/build.gradle.kts

@@ -10,8 +10,6 @@ plugins {
 val compilerModules: Array<String> by rootProject.extra
 val otherCompilerModules = compilerModules.filter { it != path }
 
-val tasksWithWarnings: List<String> by rootProject.extra
-
 val effectSystemEnabled: Boolean by rootProject.extra
 val newInferenceEnabled: Boolean by rootProject.extra
 
@@ -87,16 +85,6 @@ if (kotlinBuildProperties.isInJpsBuildIdeaSync) {
     idea {
         this.module.generatedSourceDirs.add(generationRoot)
     }
-} else {
-    allprojects {
-        tasks.withType<KotlinCompile<*>> {
-            if (path !in tasksWithWarnings) {
-                kotlinOptions {
-                    allWarningsAsErrors = true
-                }
-            }
-        }
-    }
 }
 
 projectTest(parallel = true) {

compiler/cli/build.gradle.kts

@@ -57,7 +57,7 @@ tasks.withType<org.jetbrains.kotlin.gradle.dsl.KotlinCompile<*>> {
     kotlinOptions {
         languageVersion = "1.3"
         apiVersion = "1.3"
-        freeCompilerArgs = freeCompilerArgs - "-progressive" + "-Xskip-prerelease-check"
+        freeCompilerArgs += "-Xskip-prerelease-check"
     }
 }