hush: fix handling of } which is not a closing one in { cmd; }

function                                             old     new   delta
parse_stream                                        2176    2302    +126
builtin_unset                                        381     387      +6

diff --git a/shell/hush_test/hush-parsing/group1.right b/shell/hush_test/hush-parsing/group1.right
new file mode 100644
index 0000000..6a7c4be
--- /dev/null
+++ b/shell/hush_test/hush-parsing/group1.right
@@ -0,0 +1 @@
+word} }
diff --git a/shell/hush_test/hush-parsing/group1.tests b/shell/hush_test/hush-parsing/group1.tests
new file mode 100644
index 0000000..f063fbc
--- /dev/null
+++ b/shell/hush_test/hush-parsing/group1.tests
@@ -0,0 +1 @@
+{ echo word} }; }