Add back ScalaValueClasses() initialization

The call to `apply` perform side effects that need to be executed

Author: lolgab

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -2133,6 +2133,7 @@ class Definitions {
       // force initialization of every symbol that is synthesized or hijacked by the compiler
       syntheticCoreClasses
       syntheticCoreMethods
+      ScalaValueClasses()
       JavaEnumClass
       // end force initialization
       isInitialized = true