Use FirModuleBasedSession with module info, use platform default imports

In this commit, FIR sessions made bound to a particular module

compiler/fir/tree/build.gradle.kts

@@ -11,6 +11,7 @@ plugins {
 jvmTarget = "1.6"
 
 dependencies {
+    compile(project(":compiler:frontend.common"))
     compile(project(":core:descriptors"))
     compile(project(":compiler:fir:cones"))
     compile(project(":compiler:ir.tree"))

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSession.kt

@@ -5,10 +5,11 @@
 
 package org.jetbrains.kotlin.fir
 
+import org.jetbrains.kotlin.analyzer.ModuleInfo
 import kotlin.reflect.KClass
 
 interface FirSession {
-
+    val moduleInfo: ModuleInfo?
 
     val components: Map<KClass<*>, Any>
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSessionBase.kt

@@ -5,15 +5,18 @@
 
 package org.jetbrains.kotlin.fir
 
+import org.jetbrains.kotlin.analyzer.ModuleInfo
 import kotlin.reflect.KClass
 
 abstract class FirSessionBase : FirSession {
+    override val components: MutableMap<KClass<*>, Any> = mutableMapOf()
+
+    override val moduleInfo: ModuleInfo?
+        get() = null
 
     protected fun <T : Any> registerComponent(tClass: KClass<T>, t: T) {
         assert(tClass !in components) { "Already registered component" }
         components[tClass] = t
     }
+}
 
-    override val components: MutableMap<KClass<*>, Any> = mutableMapOf()
-
-}