message: Update rustdoc tests with -Cmetadata flag
diff: @@ -32,6 +32,7 @@ fn rustdoc_args() {
  -o [CWD]/target/doc \
  [..] \
  --cfg=foo \
  + -C metadata=[..] \
  -L dependency=[CWD]/target/debug/deps [..]`
  [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  ",
  @@ -83,6 +84,7 @@ fn rustdoc_foo_with_bar_dependency() {
  -o [CWD]/target/doc \
  [..] \
  --cfg=foo \
  + -C metadata=[..] \
  -L dependency=[CWD]/target/debug/deps \
  --extern [..]`
  [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  @@ -122,6 +124,7 @@ fn rustdoc_only_bar_dependency() {
  -o [CWD]/target/doc \
  [..] \
  --cfg=foo \
  + -C metadata=[..] \
  -L dependency=[CWD]/target/debug/deps [..]`
  [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  ",
  @@ -144,6 +147,7 @@ fn rustdoc_same_name_documents_lib() {
  -o [CWD]/target/doc \
  [..] \
  --cfg=foo \
  + -C metadata=[..] \
  -L dependency=[CWD]/target/debug/deps [..]`
  [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  ",
  