Revert of Modifying TextBlobCacheTest to use SkRandomScalerContext (patchset #3 id:40001 of https://codereview.chromium.org/1266003002/)

Reason for revert:
breaking android

Original issue's description:
> Modifying TextBlobCacheTest to use SkRandomScalerContext
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/adcdca86ce425cf8c28bfad311cef028df756ee8

TBR=bungeman@google.com,bsalomon@google.com,joshualitt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1267623004
diff --git a/src/gpu/GrAtlasTextContext.cpp b/src/gpu/GrAtlasTextContext.cpp
index f597639..08fbf58 100644
--- a/src/gpu/GrAtlasTextContext.cpp
+++ b/src/gpu/GrAtlasTextContext.cpp
@@ -1678,10 +1678,8 @@
                         }
                         glyph = blob->fGlyphs[glyphOffset];
                         SkASSERT(glyph);
-                        SkASSERT(id == glyph->fPackedID);
-                        // We want to be able to assert this but cannot for testing purposes.
-                        // once skbug:4143 has landed we can revist this assert
-                        //SkASSERT(glyph->fMaskFormat == this->maskFormat());
+                        SkASSERT(id == glyph->fPackedID &&
+                                 glyph->fMaskFormat == this->maskFormat());
 
                         if (!fFontCache->hasGlyph(glyph) &&
                             !strike->addGlyphToAtlas(batchTarget, glyph, scaler, skGlyph,