Currently STANDARD_SCRIPT_VERIFY_FLAGS is based on
MANDATORY_SCRIPT_VERIFY_FLAGS which doesn't really make
sense as that flag set has to do with banning behaviour.
It's better to be explicit about all the most strict rules
that transactions need to be relayable for the sake of tests
This helps clear up some possible misunderstandings.
For example, SCRIPT_VERIFY_MINIMALDATA was included in the
definition of STANDARD_SCRIPT_VERIFY_FLAGS but it was actually
in MANDATORY_SCRIPT_VERIFY_FLAGS too, which may have given the
wrong impression about the fact that minimaldata violations
are banworthy. (oversight from D4679, when mandatory flags
were defined in another file)
There is no change in the value of the flagset here, it
is 0x7547EF both before and after this Diff.
Depends on D5220