In the final step for preserving typedef info better in the AST, upgrade

isPointerType and isVectorType to only look through a single level of typedef
when one is present.  For this invalid code:

typedef float float4 __attribute__((vector_size(16)));
typedef int int4 __attribute__((vector_size(16)));
typedef int4* int4p;
void test(float4 a, int4p result, int i) {
    result[i] = a;
}

we now get:

t.c:5:15: error: incompatible types assigning 'float4' to 'int4'
    result[i] = a;
    ~~~~~~~~~ ^ ~

instead of:

t.c:5:15: error: incompatible types assigning 'float4' to 'int  __attribute__((vector_size(16)))'
    result[i] = a;
    ~~~~~~~~~ ^ ~

The rest of the type predicates should be upgraded to do the same thing.

llvm-svn: 39932