Use Plugins DSL in Kotlin Gradle scripts

When plugins DSL is used, there is no need to
manually generate typesafe accessors for extensions and
conventions (by running `./gradlew kotlinDslAccessorsSnapshot`).

compiler/incremental-compilation-impl/build.gradle.kts

@@ -1,6 +1,8 @@
 
-apply { plugin("kotlin") }
-apply { plugin("jps-compatible") }
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
 
 jvmTarget = "1.6"