tests: check decoding of setfsgid32 syscall

* tests/setfsgid32.c: New file.
* tests/setfsgid32.test: New test.
* tests/.gitignore: Add setfsgid32.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add setfsgid32.test.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 1edd6c4..f051fc9 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -193,6 +193,7 @@
 	sendfile64 \
 	set_ptracer_any \
 	setfsgid \
+	setfsgid32 \
 	setfsuid \
 	setfsuid32 \
 	setgid \
@@ -415,6 +416,7 @@
 	sendfile.test \
 	sendfile64.test \
 	setfsgid.test \
+	setfsgid32.test \
 	setfsuid.test \
 	setfsuid32.test \
 	setgid.test \