As part of java completions for expected types, if the expected type is
a functional interface, lambda expression completions are suggested with
parameters.

Change-Id: If6fab06233e4fe517d87599522c1b99133b64e95
Signed-off-by: Gayan Perera <gayanper@gmail.com>
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.ui/+/186573
Tested-by: JDT Bot <jdt-bot@eclipse.org>
Reviewed-by: Kalyan Prasad Tatavarthi <kalyan_prasad@in.ibm.com>