gdb/testsuite: Merge whatis.exp and ctf-whatis.exp

gdb/testsuite: Merge whatis.exp and ctf-whatis.exp

The recently added gdb.base/ctf-whatis.exp test is a slightly modified
version of gdb.base/whatis.exp, with a few tests removed, and the
source compiled with different compiler options.  This patch merges
the two tests together into a single test script.

I tested using a version of GCC with CTF support added.

gdb/testsuite/ChangeLog:

	* gdb.base/ctf-whatis.c: Delete.
	* gdb.base/ctf-whatis.exp: Delete.
	* gdb.base/whatis.exp: Rewrite to compile as both dwarf and ctf.

Change-Id: I09e11c70f197b79d2b1e0ae8c86a21c622be6c51