Remove imageSupportRequired parameter to runTestHarness (#1077)

* Tests requiring image support use runTestHarnessWithCheck

Removing special case for images in runTestHarness.

Fixes #710

* Remove imageSupportRequired argument

Tests which require image support now specify this while
calling runTestHarnessWithCheck.

Fixes #710

Signed-off-by: Ellen Norris-Thompson <ellen.norris-thompson@arm.com>

test_extensions/media_sharing/main.cpp

@@ -200,5 +200,5 @@ int main(int argc, const char *argv[])
   if (!MediaSurfaceSharingExtensionInit())
     return TEST_FAIL;
 
-  return runTestHarness(argc, argv, test_num, test_list, false, true, 0);
+  return runTestHarness(argc, argv, test_num, test_list, true, 0);
 }