issue #198 tests for farray opcodes

(cherry picked from commit ea6c408c97)

tests/comptests/16_farray.lua

@@ -0,0 +1,21 @@
+f = compiler.load([[
+    return function(arr: number[], i: integer, value: number)
+        arr[i] = value
+    end
+]]
+)
+assert(f and type(f) == 'function')
+z = f()
+assert(z and type(z) == 'function')
+x = table.numarray(10)
+z(x, 1, 1.1)
+assert(x[1] == 1.1)
+z(x, 2, 2.2)
+assert(x[1] == 1.1)
+assert(x[2] == 2.2)
+z(x, 11, 11.11)
+assert(x[1] == 1.1)
+assert(x[2] == 2.2)
+assert(x[11] == 11.11)
+z(x, 12, 12)
+assert(x[12] == 12.0)