Clean up references to project directory structure

Use canonicalPath instead of absolutePath since it is absolute and
canonical.

Bug: 152627091
Test: ./gradlew bOS
Change-Id: Ibe63e5588524c9f6674fc222f5a1bfeb22c88d25
diff --git a/navigation/navigation-safe-args-generator/build.gradle b/navigation/navigation-safe-args-generator/build.gradle
index ee82964..6d7022a 100644
--- a/navigation/navigation-safe-args-generator/build.gradle
+++ b/navigation/navigation-safe-args-generator/build.gradle
@@ -37,10 +37,14 @@
 
     testImplementation(JUNIT)
     testImplementation(GOOGLE_COMPILE_TESTING)
-    testImplementation fileTree(dir: "${SdkHelperKt.getSdkPath(project.rootDir)}/platforms/$SupportConfig.COMPILE_SDK_VERSION/",
-            include : "android.jar")
-    testImplementation fileTree(dir: "${new File(project(":navigation:navigation-common").buildDir, "libJar")}",
-            include : "*.jar")
+    testImplementation fileTree(
+            dir: "${SdkHelperKt.getSdkPath(project)}/platforms/$SupportConfig.COMPILE_SDK_VERSION/",
+            include : "android.jar"
+    )
+    testImplementation fileTree(
+            dir: "${new File(project(":navigation:navigation-common").buildDir, "libJar")}",
+            include : "*.jar"
+    )
 }
 
 tasks.findByName("test").doFirst {