FilePermission Canonical path optimization

[deven you]

Hi All,
 File.getCanonicalPath() is a very time-consuming method, we observed
significant performance degradation from some application's startup stage
with java.io.FilePermission. However, lazying load the calls to
getCanonicalPath() from java.ioFilePermission is straightforward and solve
this problem effectively. Openjdk bug[1]  tracks this bug and here is the
patch [2]. Could anyone take a look?

[1] https://bugs.openjdk.java.net/browse/JDK-8066211
[2] http://cr.openjdk.java.net/~youdwei/ojdk-912/webrev.00/