Fixed clang-tidy readability-redundant-preprocessor warning

For error_test.c the removed code was already dead, because it was in the else of an `#if H5_USE_16_API` block.

Based on H5Location.h, I think p_get_ref_obj_type was meant to be in `#ifndef DOXYGEN_SHOULD_SKIP_THIS` and an `#endif` was missing.  Similarly, in the header, getObjTypeByIdx is only in H5_NO_DEPRECATED_SYMBOLS, not DOXYGEN_SHOULD_SKIP_THIS.

c++/src/H5Location.cpp

@@ -398,6 +398,7 @@ H5Location::getComment(const H5std_string &name, size_t buf_size) const
 {
     return (getComment(name.c_str(), buf_size));
 }
+
 #ifndef DOXYGEN_SHOULD_SKIP_THIS
 
 //--------------------------------------------------------------------------
@@ -646,6 +647,7 @@ H5Location::p_get_obj_type(void *ref, H5R_type_t ref_type) const
     return (obj_type);
 }
 #endif // DOXYGEN_SHOULD_SKIP_THIS
+
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 //--------------------------------------------------------------------------
@@ -704,6 +706,7 @@ H5Location::p_get_ref_obj_type(void *ref, H5R_type_t ref_type) const
     }
     return (obj_type);
 }
+#endif // DOXYGEN_SHOULD_SKIP_THIS
 
 //--------------------------------------------------------------------------
 // Function:    H5Location::getRegion
@@ -2294,7 +2297,6 @@ H5Location::childObjVersion(const H5std_string &objname) const
 }
 
 #ifndef H5_NO_DEPRECATED_SYMBOLS
-#ifndef DOXYGEN_SHOULD_SKIP_THIS
 //--------------------------------------------------------------------------
 // Function:    H5Location::getObjTypeByIdx
 ///\brief       Returns the type of an object in this group, given the
@@ -2372,7 +2374,6 @@ H5Location::getObjTypeByIdx(hsize_t idx, H5std_string &type_name) const
     return (obj_type);
 }
 
-#endif // DOXYGEN_SHOULD_SKIP_THIS
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 //--------------------------------------------------------------------------
@@ -2433,6 +2434,4 @@ f_DataSpace_setId(DataSpace *dspace, hid_t new_id)
 //--------------------------------------------------------------------------
 H5Location::~H5Location() {}
 
-#endif // DOXYGEN_SHOULD_SKIP_THIS
-
 } // namespace H5

test/error_test.c

@@ -129,13 +129,8 @@ test_error(hid_t file)
         TEST_ERROR;
     if (old_data != NULL)
         TEST_ERROR;
-#ifdef H5_USE_16_API
-    if (old_func != (H5E_auto_t)H5Eprint)
-        TEST_ERROR;
-#else  /* H5_USE_16_API */
     if (old_func != (H5E_auto2_t)H5Eprint2)
         TEST_ERROR;
-#endif /* H5_USE_16_API */
 
     if (H5Eset_auto2(H5E_DEFAULT, NULL, NULL) < 0)
         TEST_ERROR;