THRIFT-3337 Add testBool method to cross tests

This closes #611
diff --git a/test/go/src/common/simple_handler.go b/test/go/src/common/simple_handler.go
index 97ff52d..944f11c 100644
--- a/test/go/src/common/simple_handler.go
+++ b/test/go/src/common/simple_handler.go
@@ -37,6 +37,10 @@
 	return thing, nil
 }
 
+func (p *simpleHandler) TestBool(thing []byte) (r []byte, err error) {
+	return thing, nil
+}
+
 func (p *simpleHandler) TestByte(thing int8) (r int8, err error) {
 	return thing, nil
 }