Remove SK_SUPPORT_LEGACY_TEXTBLOB_BUILDER.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2988

Change-Id: Ib39913a67cdd05662e7a91b4f05fbe5429eb0c42
Reviewed-on: https://skia-review.googlesource.com/2988
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Ben Wagner <benjaminwagner@google.com>

include/core/SkTextBlob.h

@@ -106,12 +106,6 @@ public:
      */
     sk_sp<SkTextBlob> make();
 
-#ifdef SK_SUPPORT_LEGACY_TEXTBLOB_BUILDER
-    const SkTextBlob* build() {
-        return this->make().release();
-    }
-#endif
-
     /**
      *  Glyph and position buffers associated with a run.
      *