Extend tautological pointer compare and pointer to bool conversion warnings to

macro arguments.

Previously, these warnings skipped any code in a macro expansion.  Preform an
additional check and warn when the expression and context locations are both
in the macro argument.

The most obvious case not caught is passing a pointer directly to a macro,
i.e 'assert(&array)' but 'assert(&array && "valid array")' is caught.  This is
because macro arguments are not typed and the conversion happens inside the
macro.

llvm-svn: 215251