test: Don't ignore test output files left in test directory

Tests should be placing output files in the output/ directory now,
although not all tests follow this standard practice.  Drop the
"*.out.*" from .gitignore to make improper test behavior more evident.

Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Signed-off-by: Uli Schlachter <psychon@znc.in>
test: Fix several tests to place output files in the output directory

The standard location for test output is cairo/test/output.  The harness
itself was updated to write automatically generated images in this
directory, however a number of tests generate their own local output
files.

This patch updates these tests to write their output into
CAIRO_TEST_OUTPUT_DIR (which defaults to cairo/test/output) as well, in
the interest of decluttering the test directory.

Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Signed-off-by: Uli Schlachter <psychon@znc.in>
test: Make cairo_test_mkdir() usable throughout tests.

Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Signed-off-by: Uli Schlachter <psychon@znc.in>
test: Ensure output dirs exist, falling back to current dir if needed

This change makes several tests behave more like ps-eps.c, et al by
making them attempt to mkdir "output", and in case of trouble use "."
instead.  filenames are now allocated at runtime due to this change, so
ensure the corresponding free()'s are in place as well.

This should facilitate running the test suite with a relative path
outside cairo's source tree, such as when employing the CAIRO_REF_DIR
environment variable.

Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Signed-off-by: Uli Schlachter <psychon@znc.in>
svg, test: Refer to output filename by variable, not a hardcoded value

Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Signed-off-by: Uli Schlachter <psychon@znc.in>