After the SRID column attribute was introduced (WL#8592), the query
optimizer refuses to consider spatial indexes over columns without the SRID
attribute. Thus, we should raise a warning when a user creates a spatial
index over a SRID-less column. This patch adds this warning, and adjusts
a good amount of MTR tests to include the SRID attribute in order to
avoid having a lot of warnings in the test files.

Change-Id: Idd1b5560328191f66078c6d861921df067fc37fb
(cherry picked from commit 8c11442ccb3330abb53e97c48bd56b63f5a99e2d)