Fix build error formatting (#3477)

CTest stopped adding trailing newlines to the `Build.xml` `<Text>`
element sometime between the versions used to generate most of the test
data and the most recent version of CTest. This commit resolves the
issue by ensuring that exactly one newline is placed between the Text
and PostContext.

Author: williamjallen

app/cdash/app/Model/BuildError.php

@@ -18,6 +18,7 @@
 namespace CDash\Model;
 
 use App\Models\BasicBuildAlert;
+use Illuminate\Support\Str;
 
 /** BuildError */
 class BuildError
@@ -54,7 +55,7 @@ public function Insert(): void
             'sourceline' => (int) $this->SourceLine,
             'repeatcount' => (int) $this->RepeatCount,
             'newstatus' => 0,
-            'stdoutput' => $this->PreContext . $this->Text . $this->PostContext,
+            'stdoutput' => $this->PreContext . Str::rtrim($this->Text) . PHP_EOL . $this->PostContext,
             'stderror' => $this->Text,
         ]);
     }