tests/tcg: Fix compilation of test_path

tests/tcg: Fix compilation of test_path

The test_path binary is (unlike the other test binaries in tests/tcg)
actually intended to be compiled with the same compiler used to build
the main QEMU executables. It actually #includes a number of the
QEMU source files in an attempt to unit-test the util/path.c functions,
and so if it is not compiled with the same compiler used by configure
to set CONFIG_ settings then it is liable to fail to build.
Fix the makefile to build it with the default C compiler rules, not
CC_I386, and fix the test itself not to include a lot of unnecessary
trace related source files which cause the build to fail if the trace
backend is anything other than 'simple'.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>