tests|lib: remove assert.h includes

Only the igt core and non-test tools should have asserts to catch
internal errors, tests and helper libraries should all user igt_asert
instead.

Fix things up where assert instead of igt_assert was used.

One tiny step towards header sanity.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

tests/pm_rps.c

@@ -197,7 +197,7 @@ static void emit_store_dword_imm(uint32_t val)
 #define LOAD_HELPER_BO_SIZE (16*1024*1024)
 static void load_helper_set_load(enum load load)
 {
-	assert(lh.igt_proc.running);
+	igt_assert(lh.igt_proc.running);
 
 	if (lh.load == load)
 		return;