overhaul ScalafixArgumentsSuite to test Scala 3

- avoid side effects & input duplication by using a fixture function
- ExplicitResultsTypes -> RemoveUnused (available in Scala 3)
- ProcedureSyntax (syntax not even supported in 3) -> RedundantSyntax
- remove tests no longer relevant (Scala 3 is tested everywhere else)
- run tests on windows by removing custom target root (tested elsewhere)

scalafix-tests/integration/src/test/scala-2/scalafix/tests/util/compat/CompatSemanticdb.scala

@@ -6,12 +6,6 @@ import scala.tools.nsc.Main
 
 object CompatSemanticdb {
 
-  def scalacOptions(src: Path, target: Path): Array[String] = {
-    Array[String](
-      s"-P:semanticdb:targetroot:$target"
-    ) ++ scalacOptions(src)
-  }
-
   def scalacOptions(src: Path): Array[String] = {
     Array[String](
       "-Yrangepos",

scalafix-tests/integration/src/test/scala-3/scalafix/tests/util/compat/CompatSemanticdb.scala

@@ -6,15 +6,10 @@ import dotty.tools.dotc.Main
 
 object CompatSemanticdb {
 
-  def scalacOptions(src: Path, target: Path): Array[String] = {
-    Array[String](
-      s"-semanticdb-target:$target"
-    ) ++ scalacOptions(src)
-  }
-
   def scalacOptions(src: Path): Array[String] = {
     Array[String](
-      "-Xsemanticdb"
+      "-Xsemanticdb",
+      s"-sourceroot:$src"
     )
   }