Fix: SEGV in CIccCalculatorFunc::ApplySequence()

[ChrisCoxArt]

Test before adding to avoid overflow.
And add one defensive check to try and catch overflow. (assuming that 0x80000000 ops are not actually possible).
Fixes #644

Pull Request Checklist

• Have you followed the guidelines in Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you built your Pull Request locally with the Build Instructions?
• Have you added or updated relevant tests?
• Have you added or updated relevant docs?

[xsscx]

2026-03-07 22:34:50 UTC

[xsscx]

Maintainer Repro

2026-03-07 22:44:36 UTC

[2026-03-07 22:44:36 UTC] ~/pr-652/iccDEV/Build (pr-652)$
...  
mkdir pr-652
cd pr-652
git clone https://github.com/InternationalColorConsortium/iccDEV.git
cd iccDEV
git fetch origin pull/652/head:pr-652
git checkout pr-652
cd Build
export CXX=clang++ && export CXXFLAGS="-fsanitize=address,undefined -fno-omit-frame-pointer -g -O1 -fprofile-arcs -ftest-coverage" && export LDFLAGS="-fsanitize=address,undefined -fprofile-arcs" && cmake Cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -DENABLE_ASAN=ON -DENABLE_UBSAN=ON -DENABLE_COVERAGE=ON
make -j32
...
ASAN_OPTIONS=detect_leaks=0:print_scariness=1 Tools/IccApplyProfiles/iccApplyProfiles foo.tif bar.tif 0 0 0 0 0 hbo-CIccCalculatorFunc-ApplySequence-IccMpeCalc_cpp-Line3715.
icc 1
100%

[xsscx]

GHSA-vgr5-3xqx-vcqx