tests: Add required context argument to locations where omitted.

This resolves a number of red squiggles in the tests for the
`RemoteGraphQLDataSource` class since the `process` method on that class
requires the `context` argument to be defined.

These squiggles were correct, but our tests tolerate those type errors, it
seems. (We should probably fix that, as I believe our tests should be
strongly typed with few, clearly annotated exceptions.)

cc @trevor-scheer @queerviolet as an FYI, since I'm slipping this small
change in past PR review.

Author: abernix

packages/apollo-gateway/src/datasources/__tests__/RemoteGraphQLDataSource.test.ts

@@ -72,6 +72,7 @@ describe('willSendRequest', () => {
         query: '{ me { name } }',
         variables: { id: '1' },
       },
+      context: {},
     });
 
     expect(data).toEqual({ me: 'james' });
@@ -171,6 +172,7 @@ describe('error handling', () => {
 
     const result = DataSource.process({
       request: { query: '{ me { name } }' },
+      context: {},
     });
     await expect(result).rejects.toThrow(AuthenticationError);
     await expect(result).rejects.toMatchObject({
@@ -193,6 +195,7 @@ describe('error handling', () => {
 
     const result = DataSource.process({
       request: { query: '{ me { name } }' },
+      context: {},
     });
     await expect(result).rejects.toThrow(ForbiddenError);
     await expect(result).rejects.toMatchObject({
@@ -215,6 +218,7 @@ describe('error handling', () => {
 
     const result = DataSource.process({
       request: { query: '{ me { name } }' },
+      context: {},
     });
     await expect(result).rejects.toThrow(ApolloError);
     await expect(result).rejects.toMatchObject({
@@ -246,6 +250,7 @@ describe('error handling', () => {
 
     const result = DataSource.process({
       request: { query: '{ me { name } }' },
+      context: {},
     });
     await expect(result).rejects.toThrow(ApolloError);
     await expect(result).rejects.toMatchObject({