Merge 2.10.x into master

Merge remote-tracking branch 'scala/2.10.x' into master
Conflicts:
	bincompat-backward.whitelist.conf
	bincompat-forward.whitelist.conf
	src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
	src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
	src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
	src/compiler/scala/tools/nsc/util/MsilClassPath.scala
	src/compiler/scala/tools/reflect/ToolBoxFactory.scala
	src/reflect/scala/reflect/internal/Importers.scala
	src/reflect/scala/reflect/runtime/JavaMirrors.scala
	test/files/run/t6392b.check

This merge was rather involved.
Review resolution of merge conflicts in `Importers.scala` and `JavaMirrors.scala` by @xeno-by
The rest review by @retronym