Improve type conversion of SPI_processed in Python

The previous code converted SPI_processed to a Python float if it didn't
fit into a Python int.  But Python longs have unlimited precision, so
use that instead in all cases.

As in eee50a8d, we use the Python
LongLong API unconditionally for simplicity.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>

src/pl/plpython/plpy_cursorobject.c

@@ -444,9 +444,7 @@ PLy_cursor_fetch(PyObject *self, PyObject *args)
 		ret->status = PyInt_FromLong(SPI_OK_FETCH);
 
 		Py_DECREF(ret->nrows);
-		ret->nrows = (SPI_processed > (uint64) LONG_MAX) ?
-			PyFloat_FromDouble((double) SPI_processed) :
-			PyInt_FromLong((long) SPI_processed);
+		ret->nrows = PyLong_FromUnsignedLongLong(SPI_processed);
 
 		if (SPI_processed != 0)
 		{

src/pl/plpython/plpy_spi.c

@@ -371,9 +371,7 @@ PLy_spi_execute_fetch_result(SPITupleTable *tuptable, uint64 rows, int status)
 	if (status > 0 && tuptable == NULL)
 	{
 		Py_DECREF(result->nrows);
-		result->nrows = (rows > (uint64) LONG_MAX) ?
-			PyFloat_FromDouble((double) rows) :
-			PyInt_FromLong((long) rows);
+		result->nrows = PyLong_FromUnsignedLongLong(rows);
 	}
 	else if (status > 0 && tuptable != NULL)
 	{
@@ -381,9 +379,7 @@ PLy_spi_execute_fetch_result(SPITupleTable *tuptable, uint64 rows, int status)
 		MemoryContext cxt;
 
 		Py_DECREF(result->nrows);
-		result->nrows = (rows > (uint64) LONG_MAX) ?
-			PyFloat_FromDouble((double) rows) :
-			PyInt_FromLong((long) rows);
+		result->nrows = PyLong_FromUnsignedLongLong(rows);
 
 		cxt = AllocSetContextCreate(CurrentMemoryContext,
 									"PL/Python temp context",