Improved checks in font_render

[radarhere]

1. Only call text_layout once in getmask2 #7206 introduced new code to font_render, triggering https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=59831, because I didn't check that Image.core.fill didn't return NULL. I've added a fix for that, and tested it at https://github.com/radarhere/oss-fuzz/actions/runs/5296042009 and https://github.com/radarhere/oss-fuzz/actions/runs/5296052733.

2. I've also improved the memory handling by destroying the image when an error occurs.

3. Investigating https://github.com/python-pillow/Pillow/actions/runs/5262013783, I find that this failure is because of a problem checking for decompression bombs. 529621 * 541261 should be greater than Image.MAX_IMAGE_PIXELS * 2, but instead it becomes a negative number. Casting to long long first fixes that.

[radarhere]

I'm unconcerned about the Windows failures, as I believe they will be fixed once the cache is cleared by #7216

[hugovk]

There's a new UI for clearing CI cache files.

I cleared the cache by going to https://github.com/python-pillow/Pillow/actions/caches (also https://github.com/python-pillow/Pillow/actions > Management > Caches) and deleting 93478be93085fc54c3d24154a61c1a69df7fc001ac7a395ac7396f2123670bdc-b03bb08209f989d5ec95d20d01e46b3caf49b2c8e91095eb6898f612eea1518a-C:\hostedtoolcache\windows\PyPy\3.9.16\x86-17.6.33723.286, and have restarted https://github.com/python-pillow/Pillow/actions/runs/5296892543/jobs/9591206960.

[radarhere]

Thanks for the tip.

Windows is now passing. Cygwin Python 3.8 is failing however, as it is also doing on main - https://github.com/python-pillow/Pillow/actions/runs/5296887052/jobs/9595867281