pathological build time with KASAN and inline functions

[kees]

The combination of KASAN with many inline function calls appears to trigger a large increase in build times. Specifically, builds of the Linux kernel have noticed some extremely long build times for certain files/options up near a hundred of seconds. (Building the same file/options with GCC takes only a few seconds.)

This is detailed more completely here:
ClangBuiltLinux/linux#1314

A reproducer can be seen in godbolt (the clang build times out):
https://godbolt.org/z/9PGKo8