Remove the listing_meta.json file. (#4681)

The last references in CTS are removed, and the updating code in Dawn
has been deleted. So, remove the listing_meta.json file itself.

Fixed #4592

src/common/tools/gen_wpt_cts_html.ts

@@ -298,7 +298,7 @@ let config: Config;
       `Generated test variant would produce too-long -actual.txt filename. Possible solutions:
   - Reduce the length of the parts of the test query
   - Reduce the parameterization of the test
-  - Make the test function faster and regenerate the listing_meta entry
+  - Make the test function faster
   - Reduce the specificity of test expectations (if you're using them)
 |<${''.padEnd(kMaxQueryLength - 4, '-')}>|
 ${[...queryStrings.values()].join('\n')}`

src/common/tools/validate.ts

@@ -18,7 +18,6 @@ Example:
 
 Options:
   --help                     Print this message and exit.
-  --print-metadata-warnings  Print non-fatal warnings about listing_meta.json files to stderr.
   --print-case-count-report  Print the case/subcase counts of every test to stdout.
 `);
   process.exit(rc);