DatabaseMetaData returns the Cloud Spanner type names, even when used for a PostgreSQL database

[olavloite]

The DatabaseMetaData#getTypes() method returns the Cloud Spanner type names when it is used with a database with PostgreSQL dialect. This means that there is a discrepancy between the data types that the database actually supports, and what the driver reports. E.g. the driver returns type timestamp, which should be timestamptz for PostgreSQL.

The method that needs to be updated is:

java-spanner-jdbc/src/main/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaData.java

Line 920 in 9d6d313

public ResultSet getTypeInfo() {