chore: remove legacy scalastyle

When I first looked at Dotty I saw this file and it make me try to look
around at how to run it, but as far as I can tell, this isn't used. To
avoid any confusion that this is actually being used, I think we should
remove this. If this isn't the case, then it should really be enforced
in CI.

Author: ckipp01

compiler/src/dotty/tools/backend/sjs/JSCodeGen.scala

@@ -2863,14 +2863,12 @@ class JSCodeGen()(using genCtx: Context) {
 
     if (mustUseAnyComparator) {
       val equalsMethod: Symbol = {
-        // scalastyle:off line.size.limit
         val ptfm = ctx.platform
         if (lsym.derivesFrom(defn.BoxedNumberClass)) {
           if (rsym.derivesFrom(defn.BoxedNumberClass)) externalEqualsNumNum
           else if (rsym.derivesFrom(defn.BoxedCharClass)) externalEqualsNumObject // will be externalEqualsNumChar in 2.12, SI-9030
           else externalEqualsNumObject
         } else externalEquals
-        // scalastyle:on line.size.limit
       }
       genApplyStatic(equalsMethod, List(lsrc, rsrc))
     } else {

compiler/src/dotty/tools/backend/sjs/JSPositions.scala

@@ -62,7 +62,7 @@ class JSPositions()(using Context) {
   implicit def implicitSourcePos2irPos(implicit sourcePos: SourcePosition): ir.Position =
     sourceAndSpan2irPos(sourcePos.source, sourcePos.span)
 
-  private object span2irPosCache { // scalastyle:ignore
+  private object span2irPosCache {
     import dotty.tools.dotc.util._
 
     private var lastDotcSource: SourceFile = null