[ clean ] Rules.Def: removed old, commented-out code.
[ fix ] Systematically use termination pragmas when addConstant.

Generalizes Ulf's commit 9e91cc17bdbf2801a4ac55b177b2f37b218eeecb:
[ fix ] set funTerminates directly for definitions with pragmas.
[ test ] For checking copattern definition where first clause loops.
Merge branch 'maint-2.4.2'

Conflicts:
	src/full/Agda/TypeChecking/Rules/Decl.hs
	src/full/Agda/TypeChecking/Rules/Def.hs