The following code snippet detects some "impossible" huge range.

The semantic requirements of contiguous_iterator depend on pointer arithmetic, so when the underlying contiguous_range has more than 1 elements, the range must denote a contiguous element sequence of some array to be valid (otherwise, reaching from the beginning to the end causes UB). Moreover, the C++ object model doesn't permit an array object to have more than SIZE_MAX element. So we can infer that when the size of the contiguous range is too large to fit into size_t, the range must be invalid, and thus formatting it results in UB (per [iterator.requirements.general]/10, although the paragraph seemingly accidently makes infinite range invalid).

Fixes #5182.