Add more tests of calls through Procedure Linkage Table (PLT)

These test binaries contain endbr32 and endbr64 instructions,
so this PR should be committed after RetDec has moved
to Capstone 4.0.2 (avast/retdec#1086).

features/plt/rand/call-rand.c

@@ -0,0 +1,4 @@
+#include <stdlib.h>
+int main(int argc, char ** argv) {
+  return rand();
+}

features/plt/rand/test.py

@@ -0,0 +1,19 @@
+from regression_tests import *
+
+class CommonTest(Test):
+    """Output of these tests is nearly the same."""
+    settings = TestSettings(
+        input=[
+            'call-rand.x64.clang.opt0.exe',
+            'call-rand.x64.clang.opt2.exe',
+            'call-rand.x64.gcc.opt0.exe',
+            'call-rand.x64.gcc.opt2.exe',
+            'call-rand.x86.clang.opt0.exe',
+            'call-rand.x86.clang.opt2.exe',
+            'call-rand.x86.gcc.opt0.exe',
+            'call-rand.x86.gcc.opt2.exe'
+        ])
+
+    def test_main_calls_rand(self):
+        main = self.out_c.funcs['main']
+        assert main.calls('rand')