fix: include value of INSTANCE_CONNECTION_NAME when invalid (#752)

Author: kurtisvg

core/src/main/java/com/google/cloud/sql/core/CloudSqlInstance.java

@@ -133,12 +133,14 @@ class CloudSqlInstance {
  ListeningScheduledExecutorService executor,
  ListenableFuture<KeyPair> keyPair) {
 
- this.connectionName = connectionName;
  Matcher matcher = CONNECTION_NAME.matcher(connectionName);
  checkArgument(
  matcher.matches(),
- "[%s] Cloud SQL connection name is invalid, expected string in the form of"
- + " \"<PROJECT_ID>:<REGION_ID>:<INSTANCE_ID>\".");
+ String.format(
+ "[%s] Cloud SQL connection name is invalid, expected string in the form of"
+ + " \"<PROJECT_ID>:<REGION_ID>:<INSTANCE_ID>\".",
+ connectionName));
+ this.connectionName = connectionName;
  this.projectId = matcher.group(1);
  this.regionId = matcher.group(3);
  this.instanceId = matcher.group(4);