HDF5 API test updates (#3835)

* HDF5 API test updates

Removed test duplication from bringing API tests
back into the library from external VOL tests
repo

Synced changes between API tests and library's
tests

Updated API tests CMake code to directly use and
install testhdf5, testphdf5, etc. instead of
creating duplicate binaries

Added new h5_using_native_vol() test function to
determine whether the VOL connector being used
is (or the VOL connector stack being used resolves
to) the native VOL connector

* Remove duplicate variable

test/API/H5_api_dataset_test.c

@@ -10817,8 +10817,8 @@ test_read_partial_chunk_hyperslab_selection(void)
  * then read correctly when the selection used in a chunked
  * dataset's file dataspace is a point selection.
  */
-#define FIXED_DIMSIZE       25
-#define FIXED_CHUNK_DIMSIZE 10
+/* #define FIXED_DIMSIZE       25 */
+/* #define FIXED_CHUNK_DIMSIZE 10 */
 static int
 test_read_partial_chunk_point_selection(void)
 {
@@ -10827,8 +10827,8 @@ test_read_partial_chunk_point_selection(void)
 
     return 1;
 }
-#undef FIXED_DIMSIZE
-#undef FIXED_CHUNK_DIMSIZE
+/* #undef FIXED_DIMSIZE */
+/* #undef FIXED_CHUNK_DIMSIZE */
 
 /*
  * A test to verify that H5Dvlen_get_buf_size returns