[Test] Read default target version from sys property in new test infra

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/services/configuration/JvmEnvironmentConfigurator.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.codegen.forTestCompile.ForTestCompileRuntime
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.config.CompilerConfigurationKey
 import org.jetbrains.kotlin.config.JVMConfigurationKeys
+import org.jetbrains.kotlin.config.JvmTarget
 import org.jetbrains.kotlin.platform.jvm.JvmPlatforms
 import org.jetbrains.kotlin.test.ConfigurationKind
 import org.jetbrains.kotlin.test.TestJdkKind
@@ -41,6 +42,8 @@ import java.io.File
 class JvmEnvironmentConfigurator(testServices: TestServices) : EnvironmentConfigurator(testServices) {
     companion object {
         val TEST_CONFIGURATION_KIND_KEY = CompilerConfigurationKey.create<ConfigurationKind>("ConfigurationKind")
+
+        private val DEFAULT_JVM_TARGET_FROM_PROPERTY: String? = System.getProperty("kotlin.test.default.jvm.target")
     }
 
     override val directivesContainers: List<DirectivesContainer>
@@ -66,6 +69,7 @@ class JvmEnvironmentConfigurator(testServices: TestServices) : EnvironmentConfig
             1 -> configuration.put(JVMConfigurationKeys.JVM_TARGET, targets.single())
             else -> error("Too many jvm targets passed: ${targets.joinToArrayString()}")
         }
+        configureDefaultJvmTarget(configuration)
 
         when (extractJdkKind(registeredDirectives)) {
             TestJdkKind.MOCK_JDK -> {
@@ -145,6 +149,24 @@ class JvmEnvironmentConfigurator(testServices: TestServices) : EnvironmentConfig
         initBinaryDependencies(module, configuration)
     }
 
+    private fun configureDefaultJvmTarget(configuration: CompilerConfiguration) {
+        if (DEFAULT_JVM_TARGET_FROM_PROPERTY == null) return
+        val customDefaultTarget = JvmTarget.fromString(DEFAULT_JVM_TARGET_FROM_PROPERTY)
+            ?: error("Can't construct JvmTarget for $DEFAULT_JVM_TARGET_FROM_PROPERTY")
+        val originalTarget = configuration[JVMConfigurationKeys.JVM_TARGET]
+        if (originalTarget == null || customDefaultTarget.majorVersion > originalTarget.majorVersion) {
+            // It's not safe to substitute target in general
+            // cause it can affect generated bytecode and original behaviour should be tested somehow.
+            // Original behaviour testing is perfomed by
+            //
+            //      codegenTest(target = 6, jvm = "Last", jdk = mostRecentJdk)
+            //      codegenTest(target = 8, jvm = "Last", jdk = mostRecentJdk)
+            //
+            // in compiler/tests-different-jdk/build.gradle.kts
+            configuration.put(JVMConfigurationKeys.JVM_TARGET, customDefaultTarget)
+        }
+    }
+
     private fun extractJdkKind(registeredDirectives: RegisteredDirectives): TestJdkKind {
         val fullJdkEnabled = JvmEnvironmentConfigurationDirectives.FULL_JDK in registeredDirectives
         val jdkKinds = registeredDirectives[JvmEnvironmentConfigurationDirectives.JDK_KIND]