ntroduce clang_getSpellingLocation() into libclang, to provide the

location where we're spelling a token even within a
macro. clang_getInstantiationLocation() tells where we instantiated
the macro.

I'm still not thrilled with the CXSourceLocation/CXSourceRange APIs,
since they gloss over macro-instantiation information.

Take 2: this time, adjusted tests appropriately and used a "simple"
approach to the spelling location.

llvm-svn: 118495