FreeType bitmap glyphs never have a path.

If a glyph is to be drawn from a bitmap, preemptively mark it as not
having any path. This prevents attempts to fake bold or draw large
`sbix` glyphs from paths.

Change-Id: I2959f18e70f29b13ca198a710dffc88a249c73d2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/517617
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>

src/ports/SkFontHost_FreeType.cpp

@@ -1298,6 +1298,8 @@ void SkScalerContext_FreeType::generateMetrics(SkGlyph* glyph, SkArenaAlloc* all
         updateGlyphIfLCD(glyph);
 
     } else if (fFace->glyph->format == FT_GLYPH_FORMAT_BITMAP) {
+        glyph->setPath(alloc, nullptr, false);
+
         if (this->isVertical()) {
             FT_Vector vector;
             vector.x = fFace->glyph->metrics.vertBearingX - fFace->glyph->metrics.horiBearingX;