Remove useless SkASSERT in SkRect.h and SkRegion.h

The pointer of reference is always not-null. It causes >50k lines of warnning when chromium is compiled by clang.
Warning looks like
../../third_party/skia/include/core/SkRect.h:284:19: warning: reference cannot be bound to dereferenced null pointer in well-defined C++ code; pointer may be assumed to always convert to true [-Wundefined-bool-conversion]
    do { if (&r) break; SkNO_RETURN_HINT(); SkDebugf_FileLine("../../third_party/skia/include/core/SkRect.h", 284, false, "%s:%d: failed assertion \"%s\"\n", "../../third_party/skia/include/core/SkRect.h", 284, "&r"); SkDebugf_FileLine("../../third_party/skia/include/core/SkRect.h", 284, true, "SK_CRASH"); } while (false);

Review URL: https://codereview.chromium.org/1111013002
2 files changed