Disable File.getCanonicalPath caches.

File.getCanonicalPath has to always return accurate
results in all cases, not doing so has potential
security implications. Caches may have stale data
if underlaying files were modified by another process
or code that's not aware of cannonical path cache.

Test: vogar ojluni/src/main/java/java/io/FileSystem.java
Bug: 62301183
Change-Id: I76b0ca606405a958ebbc57a8a6c08deb53ea1dfc