tests: Require run-fail ui tests to have an exit code (SIGABRT not ok)

Normally a `run-fail` ui test shall not be terminated by a signal like
SIGABRT. So begin having that as a hard requirement.

Some of our current tests do terminate by a signal however. Introduce
and use `run-crash` for those tests.

Author: Enselic

src/tools/compiletest/src/common.rs

@@ -110,11 +110,22 @@ string_enum! {
     }
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
+pub enum RunFailMode {
+    /// Running the program must exit with an exit code >= 1 && <= 127. If the
+    /// program is terminated by a signal (or the exit code indicates abnormal
+    /// exit) the test will fail.
+    FailureExitCode,
+    /// The running program must have crashed, e.g. by SIGABRT on Unix or
+    /// Windows by setting an appropriate NTSTATUS high bit in the exit code.
+    Crash,
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
 pub enum FailMode {
     Check,
     Build,
-    Run,
+    Run(RunFailMode),
 }
 
 string_enum! {

src/tools/compiletest/src/directive-list.rs

@@ -241,6 +241,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "regex-error-pattern",
     "remap-src-base",
     "revisions",
+    "run-crash",
     "run-fail",
     "run-flags",
     "run-pass",