The previous names (RGBA32 and RGB32) were misleading since that's not
the actual byte order in memory. The new names reflect exactly how the
color values get laid out in bitmap data.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
I overlooked a corner case where we might call the built-in ctz() on zero.
Furthermore, the calculation of the shift was wrong and the results were often
unusable.
Both issue were caused by a forgotten 36daeee34f.
This time I made sure to look at bmpsuite_files first, and now they look good.
Found by OSS-Fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28985