[libFuzzer] use proto_deps javascript_parser_proto

I will deprecate deps in proto_library for improved build throughput.
And we can use proto_deps here instead.

Bug: 938011
Change-Id: I4ce34aec6299e1eb2b70436714a5d02031041859
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504604
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Commit-Queue: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638111}

testing/libfuzzer/fuzzers/BUILD.gn

@@ -400,9 +400,7 @@ proto_library("javascript_parser_proto") {
   sources = [
     "$target_gen_dir/javascript_parser.proto",
   ]
-  deps = [
-    ":gen_javascript_parser_proto",
-  ]
+  proto_deps = [ ":gen_javascript_parser_proto" ]
   proto_out_dir = ""
 }