Regres: Include failure reasons in CI message

Change-Id: I8aed6a72c4b9a2a575e441b846c581a67f82cf9b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/28351
Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/tests/regres/main.go b/tests/regres/main.go
index 257167d..4219dee 100644
--- a/tests/regres/main.go
+++ b/tests/regres/main.go
@@ -1014,8 +1014,15 @@
 				} else {
 					sb.WriteString(fmt.Sprintf(" - [%s]", n.Status))
 				}
+				sb.WriteString("\n")
+				for _, line := range strings.Split(n.Err, "\n") {
+					if line != "" {
+						sb.WriteString(fmt.Sprintf("     %v\n", line))
+					}
+				}
+			} else {
+				sb.WriteString("\n")
 			}
-			sb.WriteString("\n")
 		}
 	}