Change default target to jvm-9 in test

Author: liufengyun

compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

@@ -129,7 +129,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
         // reverse all the effects of this transformation, which would be counter-productive.
 
 
-        // TODO: enable once we change lazy val encoding
+        // TODO: enable once we change lazy val encoding (https://github.com/lampepfl/dotty/issues/7140)
         //
         // Lazy val encoding assumes bitmap fields are non-static
         //

compiler/test/dotty/tools/vulpix/TestConfiguration.scala

@@ -8,7 +8,8 @@ object TestConfiguration {
 
   val noCheckOptions = Array(
     "-pagewidth", "120",
-    "-color:never"
+    "-color:never",
+    "-target", defaultTarget
   )
 
   val checkOptions = Array(
@@ -76,4 +77,11 @@ object TestConfiguration {
 
   /** Enables explicit nulls */
   val explicitNullsOptions = defaultOptions and "-Yexplicit-nulls"
+
+  /** Default target of the generated class files */
+  private def defaultTarget: String = {
+    import scala.util.Properties.isJavaAtLeast
+
+    if isJavaAtLeast("9") then "jvm-9" else "jvm-1.8"
+  }
 }