Hack ClassFileParser to not treat Null$ or Nothing$ as modules.

They are classes.

Author: DarkDimius

src/dotty/tools/dotc/core/StdNames.scala

@@ -510,6 +510,9 @@ object StdNames {
     val wrap: N                 = "wrap"
     val zero: N                 = "zero"
     val zip: N                  = "zip"
+    val nothingRuntimeClass: N  = "scala.runtime.Nothing$"
+    val nullRuntimeClass: N     = "scala.runtime.Null$"
+
 
     val synthSwitch: N          = "$synthSwitch"
 

src/dotty/tools/dotc/core/pickling/ClassfileParser.scala

@@ -875,7 +875,9 @@ class ClassfileParser(
         val start = starts(index)
         if (in.buf(start).toInt != CONSTANT_CLASS) errorBadTag(start)
         val name = getExternalName(in.getChar(start + 1))
-        if (name.isModuleClassName) c = ctx.requiredModule(name.sourceModuleName)
+        if (name.isModuleClassName && (name ne nme.nothingRuntimeClass) && (name ne nme.nullRuntimeClass))
+          // Null$ and Nothing$ ARE classes
+          c = ctx.requiredModule(name.sourceModuleName)
         else c = classNameToSymbol(name)
         values(index) = c
       }