The ABI tools do not diff the array length. They cannot distinguish
between arrays of unknown bound (e.g., int foo[]) and arrays of zero
length (e.g., int bar[0]). To implement array diff, this commit adds
"is_of_unknown_bound" field to the ABI dumps. It defaults to false so
that it can be omitted for common cases.
Test: ./test.py ; update prebuilts/clang-tools and build
Bug: 255702405
Change-Id: I5db163eb62e95fa01377ef7202e70cc2a0e89524
3a51bf53f1