Port last of min_unit_tests, remove references to it, add composer script

tests/_test_files/js/regexes.js

@@ -0,0 +1,24 @@
+function testIssue74() {
+    return /'/;
+}
+
+!function(s) {
+    return /^[£$€?.]/.test(s);
+}();
+
+typeof  
+    / ' /;
+
+x = / [/] /;
+
+1
+
+/ foo;
+
+(2)
+
+/ foo;
+
+function(){return/foo/};
+
+function(){return typeof/foo/};