Remove skipped test

Fixes #4617

tests/testthat/test-joins.r

@@ -904,28 +904,6 @@ test_that("join accepts tz attributes (#2643)", {
   expect_equal(nrow(result), 1)
 })
 
-test_that("join takes LHS with warning if attributes inconsistent", {
-  skip("we need to talk about this https://github.com/tidyverse/dplyr/issues/4617")
-  df1 <- tibble(a = 1:2, b = 2:1)
-  df2 <- tibble(
-    a = structure(1:2, foo = "bar"),
-    c = 2:1
-  )
-
-  expect_warning(
-    out1 <- left_join(df1, df2, by = "a"),
-    "Column `a` has different attributes on LHS and RHS of join"
-  )
-  expect_warning(out2 <- left_join(df2, df1, by = "a"))
-  expect_warning(
-    out3 <- left_join(df1, df2, by = c("b" = "a")),
-    "Column `b`/`a` has different attributes on LHS and RHS of join"
-  )
-
-  expect_equal(attr(out1$a, "foo"), NULL)
-  expect_equal(attr(out2$a, "foo"), "bar")
-})
-
 test_that("common_by() message", {
   df <- tibble(!!!set_names(letters, letters))