coverage: Migrate tests/run-coverage into tests/coverage

tests/coverage/auxiliary/inline_always_with_dead_code.rs

@@ -0,0 +1,22 @@
+// compile-flags: -Cinstrument-coverage -Ccodegen-units=4 -Copt-level=0
+
+#![allow(dead_code)]
+
+mod foo {
+    #[inline(always)]
+    pub fn called() {}
+
+    fn uncalled() {}
+}
+
+pub mod bar {
+    pub fn call_me() {
+        super::foo::called();
+    }
+}
+
+pub mod baz {
+    pub fn call_me() {
+        super::foo::called();
+    }
+}