Fix test that was picking up configuration from the environment (#287)

## Changes

The test is written to specifically test one branch so it should be
isolated from the environment. Resolve the configuration with an empty
`Environment` instance to achieve this.

This test was added in #277.

## Tests

* Unit test passes.
* Confirmed it also passes when environment variables that are used in
the nightlies are set.

Author: pietern

databricks-sdk-java/src/test/java/com/databricks/sdk/core/DatabricksConfigTest.java

@@ -90,7 +90,8 @@ public void testWorkspaceLevelOidcEndpointsWithAccountId() throws IOException {
                 "{\"authorization_endpoint\":\"https://test-workspace.cloud.databricks.com/oidc/v1/authorize\"}")) {
       DatabricksConfig c =
           new DatabricksConfig().setHost(server.getUrl()).setAccountId("1234567890");
-      c.resolve();
+      c.resolve(
+          new Environment(new HashMap<>(), new ArrayList<String>(), System.getProperty("os.name")));
       assertEquals(
           c.getOidcEndpoints().getAuthorizationEndpoint(),
           "https://test-workspace.cloud.databricks.com/oidc/v1/authorize");