Revert pending `EVENT_RETURN` tests

* "Allow ambiguosity of `return` line"
  65b991bc85
* "Move to test/.excludes-prism"
  3b4ff810d2
* "Pending `EVENT_RETURN` settracefunc tests with Prism"
  a7f33c99c6

spec/ruby/core/tracepoint/inspect_spec.rb

@@ -67,7 +67,7 @@ describe 'TracePoint#inspect' do
       end
       trace_point_spec_test_return
     end
-    ruby_version_is("3.4") { line = "(?:#{line}|#{line-1})" }
+    ruby_version_is("3.4") { line -= 1 }
 
     inspect.should =~ /\A#<TracePoint:return [`']trace_point_spec_test_return'#{@path_prefix}#{__FILE__}:#{line}>\z/
   end

test/.excludes-prism/TestSetTraceFunc.rb

@@ -1,2 +0,0 @@
-exclude(:test_return, "[Bug #20457]")
-exclude(:test_return2, "[Bug #20457]")