ruby: install required files for ptest

After update to 2.7.0, it fails to start ptest of ruby with errors:

| ./test/runner.rb:11:in `require_relative': cannot load such file --
    /usr/lib64/ruby/ptest/tool/test/runner (LoadError)

and

| test/rdoc/test_rdoc_attr.rb: cannot load such file -- rdoc/version
| test/did_you_mean/spell_checking/test_key_name_check.rb: cannot load
    such file -- /usr/lib64/ruby/ptest/lib/did_you_mean

Install the required files for the ptest.

(From OE-Core rev: be161be40c88fbac8ac17776daf3bf178a2e8f5e)

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/ruby/ruby_2.7.0.bb

@@ -45,6 +45,12 @@ do_install_append_class-target () {
 
 do_install_ptest () {
     cp -rf ${S}/test ${D}${PTEST_PATH}/
+
+    install -D ${S}/tool/test/runner.rb ${D}${PTEST_PATH}/tool/test/runner.rb
+    cp -r ${S}/tool/lib ${D}${PTEST_PATH}/tool/
+    mkdir -p ${D}${PTEST_PATH}/lib
+    cp -r ${S}/lib/did_you_mean ${S}/lib/rdoc ${D}${PTEST_PATH}/lib
+
     # install test-binaries
     find $(find ./.ext -path '*/-test-') -name '*.so' -print0 \
         | tar --no-recursion --null -T - --no-same-owner --preserve-permissions -cf - \