Undo making subReader lazy

Need this for upcoming FeatureParams implementation.
diff --git a/Lib/fontTools/ttLib/tables/otBase.py b/Lib/fontTools/ttLib/tables/otBase.py
index c678d0e..b3f880f 100644
--- a/Lib/fontTools/ttLib/tables/otBase.py
+++ b/Lib/fontTools/ttLib/tables/otBase.py
@@ -557,9 +557,8 @@
 	def ensureDecompiled(self):
 		if self.compileStatus != 1:
 			return
-		subReader = self.reader.getSubReader(self.offset)
-		self.decompile(subReader, self.font)
-		del self.reader, self.font, self.offset
+		self.decompile(self.reader, self.font)
+		del self.reader, self.font
 
 	def compile(self, writer, font):
 		table = self.preWrite(font)
diff --git a/Lib/fontTools/ttLib/tables/otConverters.py b/Lib/fontTools/ttLib/tables/otConverters.py
index faaa237..8dd1824 100644
--- a/Lib/fontTools/ttLib/tables/otConverters.py
+++ b/Lib/fontTools/ttLib/tables/otConverters.py
@@ -196,8 +196,7 @@
 					% (offset, self.tableClass.__name__)
 			return None
 		table = self.tableClass()
-		table.reader = reader
-		table.offset = offset
+		table.reader = reader.getSubReader(offset)
 		table.font = font
 		table.compileStatus = 1
 		if not font.lazy: