Remove *ios* case from print-target-list Makefile

Based on the TODO, this case was added to short-circuit for ios builds,
which is no longer necessary.

The comment in this Makefile mentions rust-lang/rust#29812 as a
dependency, but that issue has been since closed, with a statement that
the ICE of concern was resolved circa 1.12.

Here we remove this case, and just run the same branch for all targets.

Signed-off-by: Kristofer Rye <kristofer.rye@gmail.com>

src/test/run-make-fulldeps/print-target-list/Makefile

@@ -2,12 +2,9 @@
 
 # Checks that all the targets returned by `rustc --print target-list` are valid
 # target specifications
-# TODO remove the '*ios*' case when rust-lang/rust#29812 is fixed
 all:
 	for target in $(shell $(BARE_RUSTC) --print target-list); do \
 		case $$target in \
-			*ios*) \
-				;; \
 			*) \
 				$(BARE_RUSTC) --target $$target --print sysroot \
 				;; \