Fix keepanno tests on Windows

Bug: b/392865072
Change-Id: I9b9e77bebba2e5045e9820586684c29b7940ec15
diff --git a/d8_r8/test/build.gradle.kts b/d8_r8/test/build.gradle.kts
index 564d0ea..3a737e9 100644
--- a/d8_r8/test/build.gradle.kts
+++ b/d8_r8/test/build.gradle.kts
@@ -433,7 +433,7 @@
     systemProperty(
       "BUILD_PROP_KEEPANNO_RUNTIME_PATH",
       extractClassesPaths(
-        "keepanno/",
+        "keepanno" + File.separator,
         keepAnnoCompileTask.outputs.files.asPath,
         keepAnnoCompileKotlinTask.outputs.files.asPath))
     systemProperty("EXAMPLES_JAVA_11_JAVAC_BUILD_DIR",
diff --git a/d8_r8/test_modules/tests_bootstrap/build.gradle.kts b/d8_r8/test_modules/tests_bootstrap/build.gradle.kts
index 18e0f2b..b040c37 100644
--- a/d8_r8/test_modules/tests_bootstrap/build.gradle.kts
+++ b/d8_r8/test_modules/tests_bootstrap/build.gradle.kts
@@ -82,7 +82,7 @@
     systemProperty(
       "BUILD_PROP_KEEPANNO_RUNTIME_PATH",
       extractClassesPaths(
-        "keepanno/",
+        "keepanno" + File.separator,,
         keepAnnoCompileTask.outputs.files.asPath,
         keepAnnoCompileKotlinTask.outputs.files.asPath))
     systemProperty("R8_WITH_RELOCATED_DEPS", mainR8RelocatedTask.outputs.files.singleFile)
diff --git a/d8_r8/test_modules/tests_java_8/build.gradle.kts b/d8_r8/test_modules/tests_java_8/build.gradle.kts
index 7637a41..4aef7cf 100644
--- a/d8_r8/test_modules/tests_java_8/build.gradle.kts
+++ b/d8_r8/test_modules/tests_java_8/build.gradle.kts
@@ -141,7 +141,7 @@
     systemProperty(
       "BUILD_PROP_KEEPANNO_RUNTIME_PATH",
       extractClassesPaths(
-        "keepanno/",
+        "keepanno" + File.separator,
         keepAnnoCompileTask.outputs.files.asPath,
         keepAnnoCompileKotlinTask.outputs.files.asPath))
     // This path is set when compiling examples jar task in DependenciesPlugin.