Add QTest testcase for the Intel Hexadecimal

Add QTest testcase for the Intel Hexadecimal

'test.hex' file is a memory test pattern stored in Hexadecimal Object
Format.  It loads at 0x10000 in RAM and contains values from 0 through
255.

The test case verifies that the expected memory test pattern was loaded.

Reviewed-by: Stefan Hajnoczi <[email protected]>
Suggested-by: Steffen Gortz <[email protected]>
Suggested-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Su Hang <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
[PMM: changed qtest_startf() to qtest_initf() to work with
 current master after the refactoring in commit 88b988c895e3c2]
Signed-off-by: Peter Maydell <[email protected]>