Fix testsuite on Windows and Mac OS X

On Windows tests fails because backslash is used at the end of
`projectUri` field. On Mac OS X Alire test failed because
there is no `realpath` on Mac OS.

Author: reznikmm

testsuite/ada_lsp/project_config.alire/alr

@@ -2,5 +2,5 @@
 set -e
 # A dummy Alire replacement for testing purposes
 while [ $# -gt 1 ] ; do shift ; done
-DIR=`dirname $(realpath $0)`
+DIR=`cd $(dirname $0); pwd`
 sed -e "s#\${DIR}#${DIR}#g" .alr_$1

testsuite/ada_lsp/show_dependencies.aggregate/test.json

@@ -179,19 +179,19 @@
                "result": [
                   {
                      "uri": "$URI{common/common_pack.ads}",
-                     "projectUri": "$URI{}${DIR_SEP}"
+                     "projectUri": "$URI{/}"
                   },
                   {
                      "uri": "$URI{common/common_pack.ads}",
-                     "projectUri": "$URI{}${DIR_SEP}"
+                     "projectUri": "$URI{/}"
                   },
                   {
                      "uri": "$URI{p/main.adb}",
-                     "projectUri": "$URI{}${DIR_SEP}"
+                     "projectUri": "$URI{/}"
                   },
                   {
                      "uri": "$URI{q/main.adb}",
-                     "projectUri": "$URI{}${DIR_SEP}"
+                     "projectUri": "$URI{/}"
                   }
                ]
             }