THRIFT-4547: Swift crosstests (#2670)

Co-authored-by: Jiayu Liu <Jimexist@users.noreply.github.com>
diff --git a/Makefile.am b/Makefile.am
index 95c610e..505951b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -78,7 +78,7 @@
 space := $(empty) $(empty)
 comma := ,
 
-CROSS_LANGS = @MAYBE_CPP@ @MAYBE_C_GLIB@ @MAYBE_CL@ @MAYBE_D@ @MAYBE_JAVA@ @MAYBE_PYTHON@ @MAYBE_PY3@ @MAYBE_RUBY@ @MAYBE_PERL@ @MAYBE_PHP@ @MAYBE_GO@ @MAYBE_NODEJS@ @MAYBE_DART@ @MAYBE_ERLANG@ @MAYBE_LUA@ @MAYBE_RS@ @MAYBE_NETSTD@ @MAYBE_NODETS@ @MAYBE_KOTLIN@
+CROSS_LANGS = @MAYBE_CPP@ @MAYBE_C_GLIB@ @MAYBE_CL@ @MAYBE_D@ @MAYBE_JAVA@ @MAYBE_PYTHON@ @MAYBE_PY3@ @MAYBE_RUBY@ @MAYBE_PERL@ @MAYBE_PHP@ @MAYBE_GO@ @MAYBE_NODEJS@ @MAYBE_DART@ @MAYBE_ERLANG@ @MAYBE_LUA@ @MAYBE_RS@ @MAYBE_NETSTD@ @MAYBE_NODETS@ @MAYBE_KOTLIN@ @MAYBE_SWIFT@
 CROSS_LANGS_COMMA_SEPARATED = $(subst $(space),$(comma),$(CROSS_LANGS))
 
 if WITH_PY3