chore: Fix compilation issue after backport conflict

Author: tgodzik

compiler/src/dotty/tools/repl/ReplDriver.scala

@@ -547,7 +547,7 @@ class ReplDriver(settings: Array[String],
         try {
           val entries = flatten(jarFile)
 
-          val existingClass = entries.filter(_.ext.isClass).find(tryClassLoad(_).isDefined)
+          val existingClass = entries.filter(_.extension == "class").find(tryClassLoad(_).isDefined)
           if (existingClass.nonEmpty)
             out.println(s"The path '$path' cannot be loaded, it contains a classfile that already exists on the classpath: ${existingClass.get}")
           else inContext(state.context):

tests/semanticdb/metac.expect

@@ -3456,7 +3456,6 @@ Text => empty
 Language => Scala
 Symbols => 12 entries
 Occurrences => 33 entries
-Diagnostics => 1 entries
 Synthetics => 4 entries
 
 Symbols:
@@ -3508,11 +3507,6 @@ Occurrences:
 [20:4..20:13): scalameta -> scala/reflect/Selectable#selectDynamic().
 [21:4..21:19): StructuralTypes -> example/StructuralTypes.
 
-Diagnostics:
-[14:20..14:23): [warning] Alphanumeric method foo is not declared infix; it should not be used as infix operator.
-Instead, use method syntax .foo(...) or backticked identifier `foo`.
-The latter can be rewritten automatically under -rewrite -source 3.4-migration.
-
 Synthetics:
 [12:2..12:6):user => reflectiveSelectable(*)
 [13:2..13:6):user => reflectiveSelectable(*)