Fix ast dumping to work with long double literals, e.g. we dump:

long double X() { return 1.0L; }

as:

long double X()
(CompoundStmt 0xb06a00 <t.c:2:17, col:32>
  (ReturnStmt 0xb068d0 <col:19, col:26>
    (FloatingLiteral 0xb02cf0 <col:26> 'long double' 1.000000)))

llvm-svn: 52080