The code implementing the C++ rules of type promotion and conversion
was too pedantic. There's no need to follow the letter of the standard,
not when we can now assume that everything is two's complement (this was
true for all architectures we supported when I wrote this code in 2014,
but wasn't required by the standard).
So we can reduce this to fewer comparisons and fewer rules, using the
size of the type, not just the type ID.
Change-Id: I3d74c753055744deb8acfffd172446b02444c0c0
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
393d5efda3