Alloc glyph image correctly for SkMask::k3D_Format.

This removes the no longer used outside Skia
SK_SUPPORT_LEGACY_EMBOSSMASKFILTER define, and either deletes the code
it guards or updates it to use the new emboss mask filter factory. This
re-enables the code to test the emboss mask filter. Also added is a test
to ensure that embossed text is drawn correctly, as before this glyphs
did not allocate the proper amount of memory for the k3D_Format which
this mask filter produces. This also fixes SkEmbossMask::Emboss to write
the whole of the mul and add planes to avoid pixel differences and
MemorySanitizer errors.

Change-Id: Ib492c72a19d6a27d140e3cd48179a3ca9ce313f5
Reviewed-on: https://skia-review.googlesource.com/70260
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Herb Derby <herb@google.com>
8 files changed