test(functional): remove faulty pending check

Problem: `functional/vimscript/api_functions_spec` skips a test if the
runtime files are not generated, but this check was broken in a
refactor.

Solution: Since runtime files are now generated for all test targets, do
not skip this test.

test/functional/vimscript/api_functions_spec.lua

@@ -1,6 +1,5 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
-local luv = require('luv')
 local neq, eq, command = helpers.neq, helpers.eq, helpers.command
 local clear, curbufmeths = helpers.clear, helpers.curbufmeths
 local exc_exec, expect, eval = helpers.exc_exec, helpers.expect, helpers.eval
@@ -156,10 +155,6 @@ describe('eval-API', function()
   end)
 
   it('are highlighted by vim.vim syntax file', function()
-    if luv.fs_stat("build/runtime/syntax/vim/generated.vim").uid == nil then
-      pending("runtime was not built, skipping test")
-      return
-    end
     local screen = Screen.new(40, 8)
     screen:attach()
     screen:set_default_attr_ids({