test: Fix tst.symbols.c

Skip symbols (e.g., ftrace_trampoline) in module __builtin__ftrace
since we cannot load the module ELF.

Fix the check for duplicate symbols in the "lookup by name" test.
Specifically, we were checking for duplicates when dtrace_lookup_by_name()
failed.  Check for duplicates when that function succeeds.  This fix
is necessitated by commit 8151fb8 "htab reduction: symtab", which
makes it hard for us to know which duplicate will be chosen.

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>

test/unittest/consumer/tst.symbols.c

@@ -110,6 +110,9 @@ int read_symbols() {
 		if (strcmp(modname, "bpf]") == 0)
 			continue;
 
+		if (strcmp(modname, "__builtin__ftrace]") == 0)
+			continue;
+
 		/*
 		 * In libdtrace/dt_module.c function dt_modsym_update(),
 		 * we skip a number of symbols.  Do not test them.  The
@@ -284,19 +287,10 @@ int check_lookup_by_name(dtrace_hdl_t *h, int specify_module) {
 	    specify_module ? " and module" : "");
 	for (i = 0; i < nsymbols; i++) {
 		nchecks++;
+
 		if (dtrace_lookup_by_name(h,
 		    specify_module ? symbols[i].modname : DTRACE_OBJ_KMODS,
 		    symbols[i].symname, &sym, &si)) {
-
-			/*
-			 * If the module has another symbol with this name,
-			 * it is okay that the lookup failed.
-			 */
-			if (duplicate(i) >= 0) {
-				n_dupl++;
-				continue;
-			}
-
 			printf("ERROR: dtrace_lookup_by_name failed\n");
 			printf("  expect:");
 			print_symbol(i);
@@ -308,6 +302,11 @@ int check_lookup_by_name(dtrace_hdl_t *h, int specify_module) {
 			    strcmp(symbols[i].symname, si.name) ||
 			    strcmp(symbols[i].modname, si.object)) {
 
+				if (duplicate(i) >= 0) {
+					n_dupl++;
+					continue;
+				}
+
 				printf("ERROR: mismatch\n");
 				printf("  expect:");
 				print_symbol(i);