Revert "[ttGlyphSet] Must deep copy var components when instantiating"

This reverts commit fe6f5bd14386d0a1f546d079f1ec38e4d2414fbf.

Better fix.

Lib/fontTools/ttLib/tables/_g_l_y_f.py

@@ -2010,6 +2010,7 @@ class GlyphVarComponent(object):
                 i += 1
             self.location = newLocation
 
+        self.transform = DecomposedTransform()
         if self.flags & (
             VarComponentFlags.HAVE_TRANSLATE_X | VarComponentFlags.HAVE_TRANSLATE_Y
         ):

Lib/fontTools/ttLib/ttGlyphSet.py

@@ -3,7 +3,7 @@
 from abc import ABC, abstractmethod
 from collections.abc import Mapping
 from contextlib import contextmanager
-from copy import copy, deepcopy
+from copy import copy
 from types import SimpleNamespace
 from fontTools.misc.fixedTools import otRound
 from fontTools.misc.loggingTools import deprecateFunction
@@ -288,14 +288,12 @@ def _setCoordinates(glyph, coord, glyfTable):
 
     if glyph.isComposite():
         assert len(coord) == len(glyph.components)
-        # Shallow copy is enough: all attributes that we change are scalars
-        glyph.components = [copy(comp) for comp in glyph.components]
+        glyph.components = [copy(comp) for comp in glyph.components]  # Shallow copy
         for p, comp in zip(coord, glyph.components):
             if hasattr(comp, "x"):
                 comp.x, comp.y = p
     elif glyph.isVarComposite():
-        # Deep copy needed because we mutate comp.transform and comp.location
-        glyph.components = [deepcopy(comp) for comp in glyph.components]
+        glyph.components = [copy(comp) for comp in glyph.components]  # Shallow copy
         for comp in glyph.components:
             coord = comp.setCoordinates(coord)
         assert not coord