testsuite: Move complex tests to their own subdirectory

It seems a bit silly to isolate them by globbing vs "*complex*"
when we can just as easily put them in their own subdirectory.

testsuite/libffi.complex/return_complex1.inc

@@ -0,0 +1,41 @@
+/* -*-c-*- */
+#include "ffitest.h"
+#include <complex.h>
+
+static _Complex T_C_TYPE return_c(_Complex T_C_TYPE c1, float fl2, unsigned int in3, _Complex T_C_TYPE c4)
+{
+  return c1 + fl2 + in3 + c4;
+}
+int main (void)
+{
+  ffi_cif cif;
+  ffi_type *args[MAX_ARGS];
+  void *values[MAX_ARGS];
+  _Complex T_C_TYPE c1, c4, rc, rc2;
+  float fl2;
+  unsigned int in3;
+  args[0] = &T_FFI_TYPE;
+  args[1] = &ffi_type_float;
+  args[2] = &ffi_type_uint;
+  args[3] = &T_FFI_TYPE;
+  values[0] = &c1;
+  values[1] = &fl2;
+  values[2] = &in3;
+  values[3] = &c4;
+
+  /* Initialize the cif */
+  CHECK(ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 4,
+		     &T_FFI_TYPE, args) == FFI_OK);
+  c1 = 127.0 + 255.0 * I;
+  fl2 = 128.0;
+  in3 = 255;
+  c4 = 512.7 + 1024.1 * I;
+
+  ffi_call(&cif, FFI_FN(return_c), &rc, values);
+  rc2 = return_c(c1, fl2, in3, c4);
+  printf ("%f,%fi vs %f,%fi\n",
+	  T_CONV creal (rc), T_CONV cimag (rc),
+	  T_CONV creal (rc2), T_CONV cimag (rc2));
+  CHECK(rc == rc2);
+  exit(0);
+}