Fix returns from within finalizers

When a return in a finalizer was reached through a return within the try
block, the backend ignored the return in the finalizer:

    try {
      try { return 1 }
      finally { return 2 }
    } finally { println() }

This expression should evaluate to 2 (it does in 2.11.8), but in 2.12.0
it the result is 1.

The Scala spec is currently incomplete, it does not say that a finalizer
should be exectuted if a return occurs within a try block, and it does
not specify what happens if also the finally block has a return.

So we follow the Java spec, which basically says: if the finally blocks
completes abruptly for reason S, then the entire try statement completes
abruptly with reason S. An abrupt termination of the try block for a
different reason R is discarded.

Abrupt completion is basically returning or throwing.

1 files changed, 36 insertions, 3 deletions

diff --git a/test/files/run/t10032.check b/test/files/run/t10032.check
index c8f0bdf034..565fe25848 100644
--- a/test/files/run/t10032.check
+++ b/test/files/run/t10032.check
@@ -1,6 +1,3 @@
-t10032.scala:72: warning: Return statement found in finally-clause, discarding its return-value in favor of that of a more deeply nested return.
-      finally { return i2 }
-                ^
 t1
  i1
  a1
@@ -22,6 +19,9 @@ t3
 t4
  i1
  i2
+t4
+ e1
+ i2
 t5
  i1
  a1
@@ -35,6 +35,10 @@ t6
  i1
  i2
  i3
+t6
+ e1
+ i2
+ i3
 t7
  i1
  a1
@@ -47,3 +51,32 @@ t8
  i2
  a1
  a2
+t8
+ e1
+ i2
+ a1
+ a2
+t9
+ i1
+ i2
+ a1
+t9
+ e1
+ i2
+ a1
+t10
+ i1
+ i2
+ i3
+t10
+ e1
+ i2
+ i3
+t11
+ i1
+ i2
+ a1
+t11
+ e1
+ i2
+ a1