Revert "Fix ElimStaticThis#transformIdent"

This reverts commit 3d240ad.
This commit got in without succeding the review.
It broke what already was working(inner static objects),
and made impossible moving static methods from companion object to companion class.

Additionally, commenting or removing assertions is not the way to go, and should not pass review.

See discussion here: dotty-staging@3d240ad

Author: DarkDimius

src/dotty/tools/dotc/Compiler.scala

@@ -67,8 +67,8 @@ class Compiler {
            new Constructors,
            new FunctionalInterfaces),
       List(new LambdaLift,   // in this mini-phase block scopes are incorrect. No phases that rely on scopes should be here
-           new Flatten,
            new ElimStaticThis,
+           new Flatten,
            new RestoreScopes),
       List(/*new PrivateToStatic,*/
            new ExpandPrivate,

src/dotty/tools/dotc/transform/ElimStaticThis.scala

@@ -9,7 +9,6 @@ import dotty.tools.dotc.core.StdNames._
 import dotty.tools.dotc.core.SymDenotations.SymDenotation
 import TreeTransforms.{MiniPhaseTransform, TransformerInfo}
 import dotty.tools.dotc.core.Types.{ThisType, TermRef}
-import Phases.Phase
 
 /** Replace This references to module classes  in static methods by global identifiers to the
  *  corresponding modules.
@@ -18,8 +17,6 @@ class ElimStaticThis extends MiniPhaseTransform {
   import ast.tpd._
   def phaseName: String = "elimStaticThis"
 
-  override def runsAfter: Set[Class[_ <: Phase]] = Set(classOf[Flatten])
-
   override def transformThis(tree: This)(implicit ctx: Context, info: TransformerInfo): Tree =
     if (!tree.symbol.is(Package) && ctx.owner.enclosingMethod.is(JavaStatic)) {
       assert(tree.symbol.is(ModuleClass))
@@ -28,12 +25,10 @@ class ElimStaticThis extends MiniPhaseTransform {
     else tree
 
   override def transformIdent(tree: tpd.Ident)(implicit ctx: Context, info: TransformerInfo): tpd.Tree = {
-    val meth = ctx.owner.enclosingMethod
-    // We cannot use meth.enclosingClass because it skips other static classes,
-    // so instead we require this phase to run after Flatten and use meth.owner
-    if (meth.is(JavaStatic) && meth.owner.is(ModuleClass)) {
+    if (ctx.owner.enclosingMethod.is(JavaStatic)) {
       tree.tpe match {
-        case TermRef(thiz: ThisType, _) if (thiz.underlying.typeSymbol == meth.owner) =>
+        case TermRef(thiz: ThisType, _) =>
+          assert(thiz.underlying.typeSymbol.is(ModuleClass))
           ref(thiz.underlying.typeSymbol.sourceModule).select(tree.symbol)
         case _ => tree
       }