fix: correct C delegation and benchmark inputs in stats/strided/dpcorr

* In `src/main.c`, wrap the delegated `stdlib_strided_dpcorrwd_ndarray`
  call with `API_SUFFIX(...)` so the symbol resolves correctly when the
  64-bit indexing ABI is selected (matches the sibling pattern in
  `stats/strided/dvariance/src/main.c`).

* In `benchmark/c/benchmark.length.c`, pass `y` (not `x` twice) as the
  second strided array in `benchmark2`, otherwise the benchmark
  correlates `x` with itself and the allocated `y` is unused.

https://claude.ai/code/session_012VgKGaXwsACnoLu7UenrRc

Author: claude

lib/node_modules/@stdlib/stats/strided/dpcorr/benchmark/c/benchmark.length.c

@@ -152,7 +152,7 @@ static double benchmark2( int iterations, int len ) {
 	c = 0.0;
 	t = tic();
 	for ( i = 0; i < iterations; i++ ) {
-		c = stdlib_strided_dpcorr_ndarray( len, x, 1, 0, x, 1, 0 );
+		c = stdlib_strided_dpcorr_ndarray( len, x, 1, 0, y, 1, 0 );
 		if ( c != c ) {
 			printf( "should not return NaN\n" );
 			break;

lib/node_modules/@stdlib/stats/strided/dpcorr/src/main.c

@@ -50,5 +50,5 @@ double API_SUFFIX(stdlib_strided_dpcorr)( const CBLAS_INT N, const double *X, co
 * @return             output value
 */
 double API_SUFFIX(stdlib_strided_dpcorr_ndarray)( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const double *Y, const CBLAS_INT strideY, const CBLAS_INT offsetY ) {
-	return stdlib_strided_dpcorrwd_ndarray( N, X, strideX, offsetX, Y, strideY, offsetY );
+	return API_SUFFIX(stdlib_strided_dpcorrwd_ndarray)( N, X, strideX, offsetX, Y, strideY, offsetY );
 }