Resolve labels within break or continue expressions

Resolve labels within break or continue expressions

gcc/rust/ChangeLog:

	* resolve/rust-late-name-resolver-2.0.cc (Late::visit): Add call
	to label resolution if there is one label.
	(Late::resolve_label): Look for labels and emit an error message on
	failure.
	* resolve/rust-late-name-resolver-2.0.h: Add function prototypes.

gcc/testsuite/ChangeLog:

	* rust/compile/nr2/exclude: Remove test.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>