Add config flags and macros to control ext-inter

Adds a dependent config flag 'interintra' to turn on/off interintra
modes altogether.
Adds a dependent config flag 'wedge' to turn on/off wedge compound
for both interinter and interintra.

Adds another macro to change wedge predictors to use
only 0, 1/2, or 1 weights.

From now, use
--enable-ext-inter --enable-wedge --enable-interintra to get the
same behavior as the old --enable-ext-inter.

Change-Id: I2e787e6994163b6b859a9d6431b87c4217834ddc
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index d37104a..a6c3207 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -9933,17 +9933,7 @@
 #if CONFIG_EXT_INTER
     if (ref_frame > INTRA_FRAME && second_ref_frame == INTRA_FRAME) {
       // Mode must by compatible
-      assert(is_interintra_allowed_mode(this_mode));
-
-#if !USE_RECT_INTERINTRA
-      // Note: If the subsampling is unequal, any block size we pick will
-      // result in either a rectangular luma block or a rectangular chroma
-      // block. So in this case, we can't use any interintra modes.
-      if (xd->plane[1].subsampling_x != xd->plane[1].subsampling_y ||
-          xd->plane[2].subsampling_x != xd->plane[2].subsampling_y)
-        continue;
-#endif  // !USE_RECT_INTERINTRA
-
+      if (!is_interintra_allowed_mode(this_mode)) continue;
       if (!is_interintra_allowed_bsize(bsize)) continue;
     }