The gcovr tool is very messy and can leave a lot of crap in the source
tree even when using build directories.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220204204335.1689602-5-alex.bennee@linaro.org>