Problems Formatting Very Small and Very Large Numbers

[oleibman]

Fix #3128 (author found a workaround but the problem remains). For some complex masks, when a cast of the cell value from float to string results in the use of scientific notation, the result of the formatting is unusable. I believe this PR solves the problem for numbers close to zero (Php cast from float to string uses scientific notation starting with 1E-5), and for a range of large numbers which are not handled correctly now.

However, I have not found a way to ensure that the results match Excel for very large numbers (1E18 or larger); this change at least ensures that the resulting string is an accurate rendition of the number (which is not the case now) even if doesn't match Excel. As an example, if you use the mask reported in the original issue 0 000.0 and enter a value of 1E90 into the cell, Excel will show it as 1 followed by 87 zeros, a space, 3 more zeros, decimal point and zero. I have not figured out how to get PhpSpreadsheet to do that; for now, it will just return the formatted value as 1 followed by 90 zeroes instead (I might have chosen to go with scientific notation instead). I will continue to think about those, but do not feel it is worth delaying the improvements in this ticket while I do so.

The affected section of code also truncated to the appropriate precision. It now rounds, as Excel does.

This seemed to be an area of code where problems might arise on 32-bit systems, and, indeed, I found something in the formatting code which had to be changed for 32-bit to work correctly. As long as I was doing that anyhow, I ran the full test suite, and found that Php8.1 had introduced some new stringencies which caused problems in a handful of places. All were found in Xls Reader, and all are corrected now.

This is:

- [x] a bugfix
- [ ] a new feature
- [ ] refactoring
- [x] additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

Provide an explanation of why this change is needed, with links to any Issues (if appropriate).
If this is a bugfix or a new feature, and there are no existing Issues, then please also create an issue that will make it easier to track progress with this PR.