[nomaster] Revert "SI-6548 reflection now correctly enters jinners"

This reverts commit 54a84a36d5b435a787d93ca48d45399136c7e162.

This is necessary to maintain binary compatibility with 2.10.0.

run/t6989.check had to be updated as it also (indirectly) tested SI-6548

Conflicts:
	test/files/lib/javac-artifacts.jar.desired.sha1
	test/files/run/t6548.check
	test/files/run/t6548/Test_2.scala