add another would-be data race compile fail test

tests/cfail/race-1.rs

@@ -0,0 +1,19 @@
+extern crate cortex_m_srp as srp;
+
+use srp::{C2, C4, P1, P3, Resource};
+
+static R1: Resource<i32, C2> = Resource::new(0);
+
+fn j1(prio: P1) {
+    R1.lock(&prio, |r1, _| {
+        // Would preempt this critical section
+        // srp::request(j2);
+    });
+}
+
+fn j2(prio: P3) {
+    srp::critical(|ceil| {
+        let r1 = R1.borrow(&prio, &ceil);
+        //~^ error
+    });
+}