For policy-specific tests, use the version before the policy was
introduced. Otherwise, use 3.5 where possible.
Also, remove `cmake_minimum_required()` and `project()` calls from
individual cases where they are handled by `CMakeLists.txt`.
Set the minimum required version of CMake high enough to avoid the
warning for CMAKE_LEGACY_CYGWIN_WIN32. The warning appears on stderr
and breaks the expected output matching.
Use makefile->IssueMessage() to print the unprocessed watch message in a
format consistent with other CMake messages and with a more complete
call stack for the access.
When a watch does not specify a command to call then variable_watch
prints out a message to stderr. Remove code after that which collects
all variable values to construct a message that is never printed.
Otherwise such code causes a READ_ACCESS watch to trigger on all
variables in the currents scope.
Reported-by: Yichao Yu <yyc1992@gmail.com>
