add testcase for shorten ice

tests/run-make/short-ice/Makefile

@@ -0,0 +1,9 @@
+include ../../run-make-fulldeps/tools.mk
+
+# ignore-windows
+
+export RUSTC := $(RUSTC_ORIGINAL)
+export TMPDIR := $(TMPDIR)
+
+all:
+	bash check.sh

tests/run-make/short-ice/check.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+RUST_BACKTRACE=1 $RUSTC src/lib.rs -Z treat-err-as-bug=1 1>$TMPDIR/rust-test-1.log 2>&1
+RUST_BACKTRACE=full $RUSTC src/lib.rs -Z treat-err-as-bug=1 1>$TMPDIR/rust-test-2.log 2>&1
+
+short=$(cat $TMPDIR/rust-test-1.log | wc -l)
+full=$(cat $TMPDIR/rust-test-2.log | wc -l)
+echo "short backtrace: $short"
+echo "full  backtrace: $full"
+
+if [ $full -gt $short ]; then
+    exit 0
+else
+    exit 1
+fi

tests/run-make/short-ice/src/lib.rs

@@ -0,0 +1,5 @@
+extern crate error_lib;
+
+fn main() {
+    println!("Hello, world!");
+}