We could never hit the #else branches for some of these methods, because
we already relied on having __builtin_*_overflow() readily available in
earlier methods.
multiplication_would_overflow() with three arguments was only used in a
test, so let's get rid of that as well.
Before, adding an overflow'n `Checked<T>` to another `Checked<T>` would
cause a verification faliure when instead it should propogate m_overflow
and allow the user to handle the overflow.
The following command was used to clang-format these files:
clang-format-18 -i $(find . \
-not \( -path "./\.*" -prune \) \
-not \( -path "./Base/*" -prune \) \
-not \( -path "./Build/*" -prune \) \
-not \( -path "./Toolchain/*" -prune \) \
-not \( -path "./Ports/*" -prune \) \
-type f -name "*.cpp" -o -name "*.mm" -o -name "*.h")
There are a couple of weird cases where clang-format now thinks that a
pointer access in an initializer list, e.g. `m_member(ptr->foo)`, is a
lambda return statement, and it puts spaces around the `->`.
