[functional tests] Remove dependency on the ThunderChez library.

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

functional-tests/fmt/mantissa.scm

@@ -0,0 +1,20 @@
+
+;; Break a positive real number down to a normalized mantissa and
+;; exponent. Default base=2, mant-size=52, exp-size=11 for IEEE doubles.
+
+
+(define mantissa+exponent
+  (case-lambda 
+    [(num) (mantissa+exponent num 2)]
+    [(num base) (mantissa+exponent num base 52)]
+    [(num base mant-size) (mantissa+exponent num base mant-size 11)]
+    [(num base mant-size exp-size)
+     (if (zero? num)
+	 (list 0 0)
+	 (let* ((bot (expt base mant-size))
+		(top (* base bot)))
+	   (let lp ((n num) (e 0))
+	     (cond
+	      ((>= n top) (lp (quotient n base) (+ e 1)))
+	      ((< n bot) (lp (* n base) (- e 1)))
+	      (else (list n e))))))]))