Don't re-create static TextEngine.__context if it already exists.
Don't re-create static TextEngine.__context if it already exists.

Also don't store __canvas as it's never used, just reference the __context.

openfl/openfl,Gama11/openfl,openfl/openfl,Gama11/openfl,Gama11/openfl,openfl/openfl,Gama11/openfl