Fixes build when pico_stdlib isn't included in the target libraries:
pico-sdk/src/rp2_common/pico_divider/divider.S:8:10: fatal error: hardware/divider_helper.S: No such file or directory
Also fixes the same error in pico_double, though I'm not sure how/why:
pico-sdk/src/rp2_common/pico_double/double_aeabi.S:9:10: fatal error: hardware/divider_helper.S: No such file or directory
- The divider state needs to be saved for __aeabi_ddiv, __aeabi_fdiv, __aeabi_dtan and __aeabi_ftan or they won't work in interrupts *(probably not used much youd hope), or on an RTOS context switch
- Refactored code out for the integer and floating point cases
- Improved the floating point 'tests' in passing to check more return values against GCC implementations
- Added floating point usage to the IRQ nesting test case
