Fixes #2731: Need better way to detect 32-bit platforms

[ekrich]

Thanks to the previous work on TargetTriple - #3258

Now we should be technically able to support all 32 bit and 64 bit with only "unknown" for 16 bit and unknown. At least there are no restrictions.

[LeeTibbert]

LGTM - Looks good to me.

Thank you for pulling one more thorn out of our collective paw.

Having to hard code the list of architectures is probably the best we can economically
do at this point. At least you found an authoritative source.

[ekrich]

Having to hard code the list of architectures is probably the best we can economically
do at this point. At least you found an authoritative source.

These are actually the architecture categories. Every architecture is covered in the parsing and there are many more. Parsing was the hard part which was done thankfully. There was only one category that was not an architecture as well and that was x86. You can see that in the test with the i386 as the example that parses to the x86 category.