Fix if bug.

Add a test 86 for more tricky if cases.

src/vm/js/QAST/Compiler.nqp

@@ -663,20 +663,21 @@ class QAST::OperationsJS {
 
             my $boolifed_cond := $comp.coerce($cond, $T_BOOL);
 
+            my $cond_without_sideeffects := Chunk.new($cond.type, $cond.expr, []);
 
             if $node.op eq 'if' {
                 $then := $comp.as_js($node[1], :$want);
 
                 if $operands == 3 {
                     $else := $comp.as_js($node[2], :$want);
                 } else {
-                    $else := $comp.coerce($cond, $want);
+                    $else := $comp.coerce($cond_without_sideeffects, $want);
                 }
             } else {
                 if $operands == 3 {
                     $then := $comp.as_js($node[2], :$want);
                 } else {
-                    $then := $comp.coerce($cond, $want);
+                    $then := $comp.coerce($cond_without_sideeffects, $want);
                 }
                 $else := $comp.as_js($node[1], :$want);
             }

src/vm/js/bin/run_tests

@@ -1,3 +1,3 @@
 #!/bin/bash
 # 19 and 30 where moved out as they were parrot specific, 52,54 is missing, we can't pass 49 till we are bootstraped
-prove -e  './nqp-js' t/nqp/{01..18}* t/nqp/{20,21,22,23,25,26,27,28,33,35,36,37,38,39,40,41,42,46,48,53,57,58,59,63,65,68,69,70,75,76,81,83}* t/js/getcomp-js.t
+prove -e  './nqp-js' t/nqp/{01..18}* t/nqp/{20,21,22,23,25,26,27,28,33,35,36,37,38,39,40,41,42,46,48,53,57,58,59,63,65,68,69,70,75,76,81,83, 86}* t/js/getcomp-js.t

t/nqp/86-more-if-tests.t

@@ -0,0 +1,4 @@
+plan(1);
+my $foo := 0;
+1 if $foo++;
+ok($foo == 1, "the if condition is evaluated once");