make junit output more consistent with default format
The default format of libtest includes new-lines between each section to ensure the label output from cargo is on it's own line
<pre><font color="#A1B56C"><b>❯</b></font> <font color="#A1B56C">cargo</font><font color="#D8D8D8"> </font><font color="#A1B56C">test</font>
<font color="#A1B56C"><b> Compiling</b></font> test-test v0.1.0 (/home/jlusby/tmp/test-test)
<font color="#A1B56C"><b> Finished</b></font> test [unoptimized + debuginfo] target(s) in 0.59s
<font color="#A1B56C"><b> Running</b></font> unittests (target/debug/deps/test_test-639f369234319c09)
running 1 test
test tests::it_works ... <font color="#A1B56C">ok</font>
test result: <font color="#A1B56C">ok</font>. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
<font color="#A1B56C"><b> Doc-tests</b></font> test-test
running 0 tests
test result: <font color="#A1B56C">ok</font>. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
</pre>
But when the junit outputter was added to libtest these newlines were omitted, resulting in some "fun" output when run via cargo.
Note the `Doc-tests` text at the end of the first line of xml.
<pre><font color="#A1B56C"><b>❯</b></font> <font color="#A1B56C">cargo</font><font color="#D8D8D8"> </font><font color="#A1B56C">test</font><font color="#D8D8D8"> </font><font color="#A1B56C">--</font><font color="#D8D8D8"> </font><font color="#A1B56C">-Zunstable-options</font><font color="#D8D8D8"> </font><font color="#A1B56C">--format</font><font color="#D8D8D8"> </font><font color="#A1B56C">junit</font>
<font color="#A1B56C"><b> Finished</b></font> test [unoptimized + debuginfo] target(s) in 0.00s
<font color="#A1B56C"><b> Running</b></font> unittests (target/debug/deps/test_test-639f369234319c09)
<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="0" tests="1" skipped="0" ><testcase classname="tests" name="it_works" time="0"/><system-out/><system-err/></testsuite></testsuites><font color="#A1B56C"><b> Doc-tests</b></font> test-test
<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="0" tests="0" skipped="0" ><system-out/><system-err/></testsuite></testsuites>
</pre>
After this PR the junit output includes the same style of newlines as the pretty format
<pre><font color="#A1B56C"><b>❯</b></font> <font color="#A1B56C">cargo</font><font color="#D8D8D8"> </font><font color="#A1B56C">test</font><font color="#D8D8D8"> </font><font color="#A1B56C">--</font><font color="#D8D8D8"> </font><font color="#A1B56C">-Zunstable-options</font><font color="#D8D8D8"> </font><font color="#A1B56C">--format</font><font color="#D8D8D8"> </font><font color="#A1B56C">junit</font>
<font color="#A1B56C"><b> Compiling</b></font> test-test v0.1.0 (/home/jlusby/tmp/test-test)
<font color="#A1B56C"><b> Finished</b></font> test [unoptimized + debuginfo] target(s) in 0.39s
<font color="#A1B56C"><b> Running</b></font> unittests (target/debug/deps/test_test-42c2320bb9450c69)
<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="0" tests="1" skipped="0" ><testcase classname="tests" name="it_works" time="0"/><system-out/><system-err/></testsuite></testsuites>
<font color="#A1B56C"><b> Doc-tests</b></font> test-test
<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="0" tests="0" skipped="0" ><system-out/><system-err/></testsuite></testsuites>
</pre>