Merge commit f26fc568402f from llvm git (by me):

Eliminate the sizing template parameter N from CoalescingBitVector

Since the parameter is not used anywhere, and the default size of 16
apparently causes PR47359, remove it. This ensures that IntervalMap
will automatically determine the optimal size, using its NodeSizer
struct.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D87044

This should fix 'Assertion failed: (Elements + Grow <= Nodes * Capacity
&& "Not enough room for elements"), function distribute, file
/usr/src/contrib/llvm-project/llvm/lib/Support/IntervalMap.cpp, line
123.' when building the x11-toolkits/py-wxPython40 port on a i386 host.

Reported by: zeising
MFC after: 6 weeks
X-MFC-With: r364284