Hide the mysql.st_spatial_reference_systems table so that it's no longer
possible to do SELECT/INSERT/UPDATE/DELETE operations on it. All
modification of the table has to be done through CREATE/DROP SPATIAL
REFERENCE SYSTEM statements.

Hiding the table means that all tests that create spatial reference
systems using INSERT statements must be rewritten to use CREATE and DROP
statements.

Some test cases are removed since they now fail in CREATE SPATIAL
REFERENCE SYSTEM instead of in each function.

Change-Id: Icf906cb92bb8c57f7b3c946379e06c2810ca4995