Migrate most of the existing coverage tests over to run-coverage

tests/run-coverage/unused.rs

@@ -0,0 +1,39 @@
+fn foo<T>(x: T) {
+    let mut i = 0;
+    while i < 10 {
+        i != 0 || i != 0;
+        i += 1;
+    }
+}
+
+fn unused_template_func<T>(x: T) {
+    let mut i = 0;
+    while i < 10 {
+        i != 0 || i != 0;
+        i += 1;
+    }
+}
+
+fn unused_func(mut a: u32) {
+    if a != 0 {
+        a += 1;
+    }
+}
+
+fn unused_func2(mut a: u32) {
+    if a != 0 {
+        a += 1;
+    }
+}
+
+fn unused_func3(mut a: u32) {
+    if a != 0 {
+        a += 1;
+    }
+}
+
+fn main() -> Result<(), u8> {
+    foo::<u32>(0);
+    foo::<f32>(0.0);
+    Ok(())
+}