tools: disable legacy indentation linting in tools

The tools directory has newer and stricter indentation enabled, but the
legacy indentation rules were not disabled. This could potentitally
result in a conflict between the two rule sets. Disable legacy linting.

PR-URL: #13895
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

tools/.eslintrc.yaml

@@ -10,3 +10,4 @@ rules:
                   MemberExpression: off,
                   ObjectExpression: first,
                   SwitchCase: 1}]
+  indent-legacy: 0