Cannot use json: true in Transaction.run query options

[howdyjessie]

It appears transaction.run ignores the json boolean that can be passed into query options. Is this intended? Seeing as transaction.read and database.run works with query.json, I expected transaction.run to also allow this flag.

Environment details

• OS: macOS 10.14
• Node.js version: 8.9.0
• npm version: 6.4.1
• @google-cloud/spanner version: 2.0.0

Steps to reproduce

1. Call transaction.run

transaction.run({
      sql: `SELECT * FROM Singers`,
      json: true,
    });

2. PartialResultStream doesn't receive query options in transaction.js
   

   nodejs-spanner/src/transaction.js

   Lines 699 to 726 in 01602ab

   	runStream(query) {
   	if (is.string(query)) {
   	query = {
   	sql: query,
   	};
   	}
   	const reqOpts = extend(
   	{
   	transaction: {},
   	},
   	codec.encodeQuery(query)
   	);
   	if (this.id) {
   	reqOpts.transaction.id = this.id;
   	} else {
   	reqOpts.transaction.singleUse = {
   	readOnly: this.options || {},
   	};
   	}
   	const makeRequest = resumeToken => {
   	return this.requestStream({
   	client: 'SpannerClient',
   	method: 'executeStreamingSql',
   	reqOpts: extend({}, reqOpts, {resumeToken: resumeToken}),
   	});
   	};
   	return new PartialResultStream(makeRequest);
   	}

3. Rows return in the usual array of arrays format instead of JSON.

It seems like PartialResultStream just needs the additional arg as written in TransactionRequest. transaction.run works as expected when the query options are passed in.

nodejs-spanner/src/transaction-request.js

Lines 225 to 228 in 01602ab

	return new PartialResultStream(makeRequest, {
	json: query.json,
	jsonOptions: query.jsonOptions,
	});

[crwilcox]

The method runStream(query) in transaction.js does not forward query.jsonOptions to the partial result stream as is done in createReadStream(table, query) in transaction-request.js. Add handling of these options for calls to runStream(query)