turn on MZ_SOFT_ASSERTIONS=1 in the testdrive binary (MaterializeInc#11725)

No reason not to

Author: umanwizard

misc/python/materialize/mzcompose/services.py

@@ -499,6 +499,7 @@ def __init__(
         if environment is None:
             environment = [
                 "TMPDIR=/share/tmp",
+                "MZ_SOFT_ASSERTIONS=1",
                 # Please think twice before forwarding additional environment
                 # variables from the host, as it's easy to write tests that are
                 # then accidentally dependent on the state of the host machine.