[functional tests] Remove dependency on the ThunderChez library.

I've just moved the relevant code into the functional-tests dir.

functional-tests/srfi/README

@@ -0,0 +1,17 @@
+
+There is an existing R6RS srfi project at:
+
+https://code.launchpad.net/~scheme-libraries-team/scheme-libraries/srfi
+
+In that project, the library names use the colon character. E.g.:
+
+    (srfi :1 lists)
+
+Filenames with a colon are not portable across UNIX and Windows. Some
+Scheme implementations support an encoding whereby ':1' is
+mapped to '%3a1'. Chez Scheme does not perform the conversion.
+
+The surfage libraries are a port of the R6RS srfi libraries to have
+names such as:
+
+    (surfage s1 lists)