Revert "Support OpenType GSUB lookupType 7 and substFormat 1"

This reverts commit ab2d641b54593df4e38e5ea3f76beb4be93bed77.

The CL has a bug that interprets the subtable offsets incorrectly.
In addition, because the current DroidSansFallback.ttf on Android
contains an incorrect GSUB table, if the CL worked correctly, the
situation would be worse because the puctuations in vertical text
will be substituted with totally unrelated glyphs.

Will reland this CL (with the bug in it fixed) after Android fixes
the incorrect GSUB table in DroidSansFallback.ttf.

BUG=287995
TBR=tony

Review URL: https://chromiumcodereview.appspot.com/23694040

git-svn-id: svn://svn.chromium.org/blink/trunk@157983 bbb929c8-8fbe-4397-9dbb-9b2b20218538