Import micro-UBSan ATF tests

These tests are used only when a distribution is built without MKSANITIZER
and without MKLIBCSANITIZER. They build the ubsan.c micro-implementation
in userland as a stan

Import micro-UBSan ATF tests

These tests are used only when a distribution is built without MKSANITIZER
and without MKLIBCSANITIZER. They build the ubsan.c micro-implementation
in userland as a standalone library (a .c file linked into tests).

The code generation part emits symbols that are handled by uUBSan.

Tested with Clang amd64 + i386 and GCC amd64 + i386.

There are two sets of tests: C code generation and C++ code generation.

There are various little differences that are handled with proper ifdefs.

Clang 7svn has significantly more checks for Undefined Behavior than GCC
5.x. Some of the tests are or might be amd64 and/or i386 specific and are
marked with proper ifdefs and comments according to the compiler
documentation.

show more ...