tests: Added numerous tests.

The tests are taken almost verbatim from the open source project PicoC. It can
be found at https://code.google.com/p/picoc/.

The tests range from very simple/trivial ones to more complicated. My view is
that the more tests the better. Without tests like this I was very reluctant to
make any changes to tcc for the fear of breaking things.

The tests pass on Win32, OSX, Linux x86 and x86_64. One or two tests fail on
each platform due to differences in the runtime library.

tests2/34_array_assignment.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+int main()
+{
+   int a[4];
+
+   a[0] = 12;
+   a[1] = 23;
+   a[2] = 34;
+   a[3] = 45;
+
+   printf("%d %d %d %d\n", a[0], a[1], a[2], a[3]);
+
+   int b[4];
+
+   b = a;
+
+   printf("%d %d %d %d\n", b[0], b[1], b[2], b[3]);
+
+   return 0;
+}
+
+/* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/