add support for call expression abstract references and more versatile tests

test/fixtures/transformation/es7-abstract-references/call/actual.js

@@ -0,0 +1,2 @@
+foo::bar();
+foo::bar("arg");

test/fixtures/transformation/es7-abstract-references/call/expected.js

@@ -0,0 +1,4 @@
+"use strict";
+
+bar[Symbol.referenceGet](foo).call(foo);
+bar[Symbol.referenceGet](foo).call(foo, "arg");

test/fixtures/transformation/es7-abstract-references/delete/actual.js

@@ -1 +1,3 @@
 delete foo::bar;
+
+if (delete foo::bar);

test/fixtures/transformation/es7-abstract-references/delete/expected.js

@@ -1,3 +1,5 @@
 "use strict";
 
 bar[Symbol.referenceDelete](foo);
+
+if ((bar[Symbol.referenceDelete](foo), true)) ;

test/fixtures/transformation/es7-abstract-references/options.json

@@ -0,0 +1,3 @@
+{
+  "experimental": true
+}

test/fixtures/transformation/es7-abstract-references/set/actual.js

@@ -1 +1,2 @@
 foo::bar = baz;
+if (foo::bar = baz);

test/fixtures/transformation/es7-abstract-references/set/expected.js

@@ -1,3 +1,4 @@
 "use strict";
 
 bar[Symbol.referenceSet](foo, baz);
+if ((bar[Symbol.referenceSet](foo, baz), baz)) ;