Failure to sink last statement in for loop with explicit loop var

[thundergnat]

The Problem

When using an explicit for loop variable, the last statement is not sunk.

Related to #1570 (Which focused on the case of for loops with implicit loop variables)

(Updated to better demonstrate the issue)

sub wat ($n) {
    1.map: -> $m { say "uno: $m" }
    1.map: -> $m { say "dos: $m" }
}

for 1 -> $p { say "|$p|"; wat($p) } # explicit for loop variable
say '';
for 1       { say "|$_|"; wat($_) } # implicit for loop variable
say '';
for 1 -> $p { say "|$p|"; sink wat($p) } # explicit for loop variable with sink

Expected Behavior

|1|
uno: 1
dos: 1

|1|
uno: 1
dos: 1

|1|
uno: 1
dos: 1

Actual Behavior

|1|
uno: 1

|1|
uno: 1
dos: 1

|1|
uno: 1
dos: 1

Environment

• Operating system:
• Compiler version (perl6 -v):
  Linux Mint 19.01 Cinnamon
  This is Rakudo version 2019.03 built on MoarVM version 2019.03
  implementing Perl 6.d.

and on Camelia: rakudo-moar a643b8b