Introduce unspecifiedJvmPlatform for clients without jvmTarget

Previously, a lot of clients used JvmPlatform as platform-marker,
without thinking about jvmTarget.

For the sake of migration, this commits introduced so-called
UnspecifiedJvmPlatform, which can be used for a time being, but
generally, all usages should be removed in  future.

idea/idea-jvm/src/org/jetbrains/kotlin/idea/configuration/KotlinJavaModuleConfigurator.kt

@@ -71,7 +71,7 @@ open class KotlinJavaModuleConfigurator protected constructor() : KotlinWithLibr
         get() = NAME
 
     override val targetPlatform: TargetPlatform
-        get() = JvmPlatforms.defaultJvmPlatform
+        get() = JvmPlatforms.unspecifiedJvmPlatform
 
     @Suppress("DEPRECATION_ERROR")
     override fun getTargetPlatform() = JvmPlatforms.CompatJvmPlatform

idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/evaluate/compilation/DebugLabelPropertyDescriptorProvider.kt

@@ -179,7 +179,7 @@ private object DebugLabelModuleDescriptor
     }
 
     override val platform: TargetPlatform?
-        get() = JvmPlatforms.defaultJvmPlatform
+        get() = JvmPlatforms.unspecifiedJvmPlatform
 
     override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName> {
         return emptyList()

idea/idea-jvm/src/org/jetbrains/kotlin/idea/framework/KotlinTemplatesFactory.kt

@@ -41,7 +41,7 @@ class KotlinTemplatesFactory : ProjectTemplatesFactory() {
         val result = mutableListOf<ProjectTemplate>(
             BuilderBasedTemplate(
                 KotlinModuleBuilder(
-                    JvmPlatforms.defaultJvmPlatform,
+                    JvmPlatforms.unspecifiedJvmPlatform,
                     "JVM | IDEA",
                     "Kotlin project with a JVM target based on the IntelliJ IDEA build system",
                     KotlinIcons.SMALL_LOGO

idea/idea-jvm/src/org/jetbrains/kotlin/idea/internal/KotlinBytecodeToolWindow.kt

@@ -286,7 +286,7 @@ class KotlinBytecodeToolWindow(private val myProject: Project, private val toolW
             if (!platform.isCommon() && !platform.isJvm()) return null
 
             val resolutionFacade = KotlinCacheService.getInstance(ktFile.project)
-                .getResolutionFacadeByFile(ktFile, JvmPlatforms.defaultJvmPlatform)
+                .getResolutionFacadeByFile(ktFile, JvmPlatforms.unspecifiedJvmPlatform)
                     ?: return null
 
             val bindingContextForFile = resolutionFacade.analyzeWithAllCompilerChecks(listOf(ktFile)).bindingContext