configs: introduce debug.config for CI-like setup

configs: introduce debug.config for CI-like setup

Some general debugging features like kmemleak, KASAN, lockdep, UBSAN etc
help fix many viruses like a microscope.  On the other hand, those
features are scatter around and mixed up with more situational debugging
options making them difficult to consume properly.  This cold help
amplify the general debugging/testing efforts and help establish
sensitive default values for those options across the broad.  This could
also help different distros to collaborate on maintaining debug-flavored
kernels.

The config is based on years' experiences running daily CI inside the
largest enterprise Linux distro company to seek regressions on
linux-next builds on different bare-metal and virtual platforms.  It can
be used for example,

  $ make ARCH=arm64 defconfig debug.config

Since KASAN and KCSAN can't be enabled together, we will need to create
a separate one for KCSAN later as well.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Qian Cai <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Daniel Thompson <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Naresh Kamboju <[email protected]>
Cc: "Stephen Rothwell" <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>