Various test fixes

Author: natsukagami

compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -235,7 +235,6 @@ class PlainPrinter(_ctx: Context) extends Printer {
         changePrec(GlobalPrec) {
           "("
           ~ keywordText("using ").provided(tp.isContextualMethod)
-          ~ keywordText("erased ").provided(tp.isErasedMethod)
           ~ keywordText("implicit ").provided(tp.isImplicitMethod && !tp.isContextualMethod)
           ~ paramsText(tp)
           ~ ")"

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -290,7 +290,6 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
         }
         "[applied to ("
         ~ keywordText("using ").provided(tp.isContextualMethod)
-        ~ keywordText("erased ").provided(tp.isErasedMethod)
         ~ argsText
         ~ ") returning "
         ~ toText(resultType)

tests/neg/safeThrowsStrawman2.scala

@@ -24,7 +24,7 @@ def bar(x: Boolean)(using CanThrow[Fail]): Int =
     val x = new CanThrow[Fail]()      // OK, x is erased
     val y: Any = new CanThrow[Fail]() // error: illegal reference to erased class CanThrow
     val y2: Any = new CTF()       // error: illegal reference to erased class CanThrow
-    println(foo(true, ctf))       // error: ctf is declared as erased, but is in fact used
+    println(foo(true, ctf))       // not error: ctf will be erased at erasure
     val a = (1, new CanThrow[Fail]()) // error: illegal reference to erased class CanThrow
     def b: (Int, CanThrow[Fail]) = ???
     def c = b._2                  // ok; we only check creation sites