Do not add .tidy files as RBE link inputs

* RBE adds implicit dependent files as inputs
  and creates too long commands.
* Adds .tidy files as validation paths.
* Change type of tidyFiles to WritablePaths.

Bug: 203577539
Test: lunch aosp_cf_arm64_phone-userdebug; USE_RBE=true WITH_TIDY=1 make
Test: USE_RBE=true WITH_TIDY=1 mm in external/skia
Change-Id: I5fc9d6f8c9c58abcd3721ca9fbae1bc785e4e609
diff --git a/cc/binary.go b/cc/binary.go
index 4d1301b..47e520d 100644
--- a/cc/binary.go
+++ b/cc/binary.go
@@ -413,7 +413,7 @@
 		linkerDeps = append(linkerDeps, deps.LateSharedLibsDeps...)
 	}
 
-	linkerDeps = append(linkerDeps, objs.tidyFiles...)
+	validations = append(validations, objs.tidyFiles...)
 	linkerDeps = append(linkerDeps, flags.LdFlagsDeps...)
 
 	// Register link action.