run_make_support: allow obtaining raw stdout/stderr

And match `stdout/stderr` lossy UTF-8 helpers.

src/tools/run-make-support/src/command.rs

@@ -222,6 +222,12 @@ pub struct CompletedProcess {
 }
 
 impl CompletedProcess {
+    #[must_use]
+    #[track_caller]
+    pub fn stdout(&self) -> Vec<u8> {
+        self.output.stdout.clone()
+    }
+
     #[must_use]
     #[track_caller]
     pub fn stdout_utf8(&self) -> String {
@@ -234,12 +240,24 @@ impl CompletedProcess {
         String::from_utf8_lossy(&self.output.stdout.clone()).to_string()
     }
 
+    #[must_use]
+    #[track_caller]
+    pub fn stderr(&self) -> Vec<u8> {
+        self.output.stderr.clone()
+    }
+
     #[must_use]
     #[track_caller]
     pub fn stderr_utf8(&self) -> String {
         String::from_utf8(self.output.stderr.clone()).expect("stderr is not valid UTF-8")
     }
 
+    #[must_use]
+    #[track_caller]
+    pub fn invalid_stderr_utf8(&self) -> String {
+        String::from_utf8_lossy(&self.output.stderr.clone()).to_string()
+    }
+
     #[must_use]
     pub fn status(&self) -> ExitStatus {
         self.output.status