[Javascript] Incorrectly generated import paths when using `google/api` or `google/type`

/cc @zchee

What version of protobuf and what language are you using?
Version: v3.6.0
Language: Javascript

What operating system (Linux, Windows, ...) and version?
Docker Image: node:9

What runtime / compiler are you using (e.g., python version or gcc version)

What did you do?
Steps to reproduce the behavior:
When using imports for google/api/.. or google/type/... the imports generated for javascript resolve to incorrect paths
Example:

import "google/api/annotations.proto";
import "google/type/date.proto";

What did you expect to see
Correctly resolved import paths

What did you see instead?
Wrongly resolved import paths:
generated output (these directories don't exist):

var google_api_annotations_pb = require('../../../../../../google/api/annotations_pb.js');
var google_type_date_pb = require('../../../../../../google/type/date_pb.js');

We resolved these imports by generating these files ourselves (from https://github.com/googleapis/googleapis repository) and copying them to the correct folder but inside of annotations_pb.js another incorrect import is generated so it seems that this problem is carrying through to any imports down the road:

// inside of annotations_pb.js 
var google_api_http_pb = require('../../../../../../google/api/http_pb.js');

We wondered how we could resolve this? Generating the files ourselves and copying them is totally ok but the wrongly generated imports inside these files are an issue we can not resolve on our end unfortunately, so any help is appreciated.

Anything else we should know about your project / environment
We use grpc_tools_node_protoc and grpc_tools_node_protoc_ts plugins to generate typescript and grpc code.

Command we execute:

# Variables:
GRPC_GATEWAY_REPO=github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis
GOOGLE_API_REPO=github.com/googleapis/googleapis
VENDOR_DIR=vendor
PROTOC_OPTION=-I. -I$(VENDOR_DIR) -I$(VENDOR_DIR)/$(GRPC_GATEWAY_REPO) -I$(VENDOR_DIR)/$(GOOGLE_API_REPO)
TYPESCRIPT_OUTPUT=gen/typescript

# Command:
grpc_tools_node_protoc $(PROTOC_OPTION) --js_out=import_style=commonjs,binary:$(TYPESCRIPT_OUTPUT) --grpc_out=$(TYPESCRIPT_OUTPUT) --plugin=protoc-gen-grpc=$(shell which grpc_tools_node_protoc_plugin)

# followed by this command for typescript generation:
protoc $(PROTOC_OPTION) --plugin=protoc-gen-ts=`which protoc-gen-ts` --ts_out=$(TYPESCRIPT_OUTPUT)

Inizia dagli import generati in annotations_pb.js e dal comando grpc_tools_node_protoc mostrato nell’issue, quindi confronta in che modo le radici di inclusione -I influiscono sui percorsi google/api e google/type. Il lavoro è completato quando gli import JavaScript generati vengono risolti correttamente, inclusi gli import transitivi come google/api/http_pb.js, senza copiare manualmente i file generati.