[Native] Don't use konan.home to determine a path to the K/N dist

A fix for KT-37550 requires us to stop using system properties when
the compiler is started from Gradle. This patch stops reading the
konan.home property to determine a path to the compiler and requires
this path to be explicitly specified in a constructor of the
Distribution class.

Issue #KT-37550

native/utils/src/org/jetbrains/kotlin/konan/target/Distribution.kt

@@ -13,22 +13,13 @@ import org.jetbrains.kotlin.konan.util.DependencyDirectories
 import org.jetbrains.kotlin.konan.util.visibleName
 
 class Distribution(
-    private val onlyDefaultProfiles: Boolean = false,
-    private val konanHomeOverride: String? = null,
-    private val runtimeFileOverride: String? = null
+        val konanHome: String,
+        private val onlyDefaultProfiles: Boolean = false,
+        private val runtimeFileOverride: String? = null
 ) {
 
     val localKonanDir = DependencyDirectories.localKonanDir
 
-    private fun findKonanHome(): String {
-        if (konanHomeOverride != null) return konanHomeOverride
-
-        val value = System.getProperty("konan.home", "dist")
-        val path = File(value).absolutePath
-        return path
-    }
-
-    val konanHome = findKonanHome()
     val konanSubdir = "$konanHome/konan"
     val mainPropertyFileName = "$konanSubdir/konan.properties"
     val experimentalEnabled by lazy {
@@ -99,10 +90,13 @@ class Distribution(
 
     val dependenciesDir = DependencyDirectories.defaultDependenciesRoot.absolutePath
 
-    fun availableSubTarget(genericName: String) =
-        additionalPropertyFiles(genericName).map { it.name }
+    val subTargetProvider = object: SubTargetProvider {
+        override fun availableSubTarget(genericName: String) =
+                additionalPropertyFiles(genericName).map { it.name }
+    }
 }
 
-fun buildDistribution(konanHomeOverride: String? = null) = Distribution(true, konanHomeOverride, null)
+// TODO: Move into K/N?
+fun buildDistribution(konanHome: String) = Distribution(konanHome,true, null)
 
-fun customerDistribution(konanHomeOverride: String? = null) = Distribution(false, konanHomeOverride, null)
+fun customerDistribution(konanHome: String) = Distribution(konanHome,false, null)

native/utils/src/org/jetbrains/kotlin/konan/target/HostManager.kt

@@ -8,12 +8,20 @@ package org.jetbrains.kotlin.konan.target
 import org.jetbrains.kotlin.konan.target.KonanTarget.*
 import java.lang.Exception
 
-open class HostManager(protected val distribution: Distribution = Distribution(), experimental: Boolean = false) {
+// TODO: Consider redesigning experimental targets support (e.g. by getting rid of such separation at all).
+open class HostManager(
+        subTargetProvider: SubTargetProvider = SubTargetProvider.NoSubTargets,
+        private val experimental: Boolean = false
+) {
+
+    constructor(
+            distribution: Distribution,
+            experimental: Boolean = false,
+    ) : this(distribution.subTargetProvider, experimental || distribution.experimentalEnabled)
 
     fun targetManager(userRequest: String? = null): TargetManager = TargetManagerImpl(userRequest, this)
 
-    private val zephyrSubtargets = distribution.availableSubTarget("zephyr").map { ZEPHYR(it) }
-    private val experimentalEnabled = experimental || distribution.experimentalEnabled
+    private val zephyrSubtargets = subTargetProvider.availableSubTarget("zephyr").map { ZEPHYR(it) }
     private val configurableSubtargets = zephyrSubtargets
 
     val targetValues: List<KonanTarget> by lazy { KonanTarget.predefinedTargets.values + configurableSubtargets }
@@ -93,7 +101,7 @@ open class HostManager(protected val distribution: Distribution = Distribution()
 
     val enabledByHost: Map<KonanTarget, Set<KonanTarget>> by lazy {
         val result = enabledRegularByHost.toMutableMap()
-        if (experimentalEnabled) {
+        if (experimental) {
             enabledExperimentalByHost.forEach { (k, v) ->
                 result.merge(k, v) { old, new -> old + new }
             }
@@ -110,7 +118,7 @@ open class HostManager(protected val distribution: Distribution = Distribution()
     }
 
     val enabled : List<KonanTarget>
-        get() = if (experimentalEnabled) enabledRegular + enabledExperimental else enabledRegular
+        get() = if (experimental) enabledRegular + enabledExperimental else enabledRegular
 
     fun isEnabled(target: KonanTarget) = enabled.contains(target)
 

native/utils/src/org/jetbrains/kotlin/konan/target/SubTargetProvider.kt

@@ -0,0 +1,14 @@
+/*
+ * 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.
+ */
+
+package org.jetbrains.kotlin.konan.target
+
+interface SubTargetProvider {
+    fun availableSubTarget(genericName: String): List<String>
+
+    object NoSubTargets : SubTargetProvider {
+        override fun availableSubTarget(genericName: String): List<String> = emptyList()
+    }
+}