Allow pre-release compiler reading pre-release binaries in tests

Pre-release compiler should be able to read pre-release binaries in tests
even if a stable language version is used, otherwise no stdlib API can be read.

compiler/tests-common/tests/org/jetbrains/kotlin/checkers/CompilerTestLanguageVersionSettings.kt

@@ -34,7 +34,7 @@ data class CompilerTestLanguageVersionSettings(
     override fun getFeatureSupport(feature: LanguageFeature): LanguageFeature.State =
             languageFeatures[feature] ?: delegate.getFeatureSupport(feature)
 
-    override fun isPreRelease(): Boolean = languageVersion.isPreRelease()
+    override fun isPreRelease(): Boolean = KotlinCompilerVersion.isPreRelease()
 
     @Suppress("UNCHECKED_CAST")
     override fun <T> getFlag(flag: AnalysisFlag<T>): T = analysisFlags[flag] as T? ?: flag.defaultValue

compiler/tests/org/jetbrains/kotlin/codegen/JvmModuleProtoBufTest.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.codegen
 
 import org.jetbrains.kotlin.cli.jvm.K2JVMCompiler
 import org.jetbrains.kotlin.config.ApiVersion
+import org.jetbrains.kotlin.config.KotlinCompilerVersion
 import org.jetbrains.kotlin.config.LanguageVersion
 import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
 import org.jetbrains.kotlin.load.kotlin.loadModuleMapping
@@ -44,7 +45,7 @@ class JvmModuleProtoBufTest : KtUsefulTestCase() {
                 "-d", tmpdir.path,
                 "-module-name", moduleName,
                 "-language-version", compileWith.versionString
-        ) + extraOptions)
+        ) + extraOptions + listOfNotNull("-Xskip-metadata-version-check".takeIf { KotlinCompilerVersion.isPreRelease() }))
 
         val mapping = ModuleMapping.loadModuleMapping(
                 File(tmpdir, "META-INF/$moduleName.${ModuleMapping.MAPPING_FILE_EXT}").readBytes(), "test",