[gcov][test] Delete UNSUPPORTED: host-byteorder-big-endian from test/profile tests

It seems that after dc52ce42, all big-endian problems have been fixed.

01899bb4 seems to have fixed XFAIL: * of
profile/instrprof-gcov-__gcov_flush-terminate.test

This essentially reverts commit 5a9b792d and
93d5ae3a.