add test for ctors not tainting fields

tests/tc_ctors/expected.txt

@@ -0,0 +1,3 @@
+identifiers
+mangleof	k
+member1	v

tests/tc_ctors/file.d

@@ -0,0 +1,19 @@
+struct Foo {
+	this(int mCtor) {}
+	int member1;
+}
+
+class Bar {
+	this(int mCtor) {}
+	int member1;
+}
+
+unittest {
+	Foo f;
+	f.m
+}
+
+unittest {
+	Bar b = new Bar(1);
+	b.m
+}

tests/tc_ctors/run.sh

@@ -0,0 +1,8 @@
+set -e
+set -u
+
+../../bin/dcd-client $1 file.d -c122 > actual.txt
+diff actual.txt expected.txt --strip-trailing-cr
+
+../../bin/dcd-client $1 file.d -c162 > actual.txt
+diff actual.txt expected.txt --strip-trailing-cr