fix: update GCloud detection on Windows

Author: kevin-wise

google-cloud-core/src/main/java/com/google/cloud/testing/BaseEmulatorHelper.java

@@ -275,13 +275,8 @@ public Process getProcess() {
  }
 
  private boolean isGcloudInstalled() {
- Map<String, String> env = System.getenv();
- for (String envName : env.keySet()) {
- if ("PATH".equals(envName)) {
- return env.get(envName).contains("google-cloud-sdk");
- }
- }
- return false;
+ String path = System.getenv("PATH");
+ return path != null && path.contains("google-cloud-sdk");
  }
 
  private boolean isEmulatorUpToDate() throws IOException, InterruptedException {