fix too much optimization for `||=`

mrbgems/mruby-compiler/core/codegen.c

@@ -1774,7 +1774,12 @@ codegen(codegen_scope *s, node *tree, int val)
         int pos;
 
         pop();
-        pos = genop_peep(s, MKOP_AsBx(name[0]=='|'?OP_JMPIF:OP_JMPNOT, cursp(), 0), NOVAL);
+        if (val) {
+          pos = genop(s, MKOP_AsBx(name[0]=='|'?OP_JMPIF:OP_JMPNOT, cursp(), 0));
+        }
+        else {
+          pos = genop_peep(s, MKOP_AsBx(name[0]=='|'?OP_JMPIF:OP_JMPNOT, cursp(), 0), NOVAL);
+        }
         codegen(s, tree->cdr->cdr->car, VAL);
         pop();
         gen_assignment(s, tree->car, cursp(), val);