[tests] Add tests to exercise various code paths in Select.replace() The original patch for bug #1190458 broke tests in CubicWeb. The patch has now been amended to fix the broken paths (namely, replacing the 'in' tests with appropriate 'is_equivalent' loops). These tests are adapted from CubicWeb's own test suite, especially those that test FTIRANK() on sqlite (the function exists but is replaced by a no-op).

\.pyc$
build/
rql_solve.so$
\.pytest\.restart$