Fix target_info.test on Windows with a hack

Add a quote character to the sed command to cause it to be quoted.
Hopefully, which will help both gnuwin and MSys versions of sed tokenize
the command line the same way.

clang-tools-extra/clangd/test/target_info.test

@@ -9,7 +9,7 @@
 # RUN: sed -e "s|INPUT_DIR|%/t.dir|g" %s > %t.test.1
 # On Windows, we need the URI in didOpen to look like "uri":"file:///C:/..."
 # (with the extra slash in the front), so we add it here.
-# RUN: sed -E -e "s|file://([A-Z]):/|file:///\1:/|g" %t.test.1 > %t.test
+# RUN: sed -E -e 's|"file://([A-Z]):/|"file:///\1:/|g' %t.test.1 > %t.test
 
 # RUN: clangd -lit-test < %t.test 2>&1 | FileCheck -strict-whitespace %t.test
 {"jsonrpc":"2.0","id":0,"method":"initialize","params":{}}