Simplify GfxResources::lookupPattern

by using the new Dict::lookup that returns the Ref if the object is a
Ref
6 jobs for simplify_lookupPattern in 14 minutes and 3 seconds (queued for 7 minutes and 45 seconds)
Status Job ID Name Coverage
  Build
passed #430599
build

00:02:51

passed #430604
build_android

00:00:55

passed #430600
build_clang_libcpp

00:02:35

passed #430603
build_clazy

00:02:58

passed #430602
build_mingw64_fedora

00:03:52

passed #430601
build_ubuntu_16_04

00:04:40