[TEST_BUG] com/sun/crypto/provider/KeyFactory/TestProviderLeak.java unstable again

This test seems to have become unstable again. Here's an example on Linux x64 (no jtreg, just running the test directly with an up-to-date build of jdk8/tl):

$ java -Xmx20m TestProviderLeak
Before memory allocation: 20020296 bytes free
OOME is thrown when allocating 17MB memory.
After memory allocation: 5511744 bytes free
Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
at java.lang.StringCoding$StringDecoder.decode(StringCoding.java:149)
at java.lang.StringCoding.decode(StringCoding.java:193)
at java.lang.String.<init>(String.java:419)
at java.lang.String.<init>(String.java:484)
at java.io.UnixFileSystem.list(Native Method)
at java.io.File.list(File.java:1122)
at javax.crypto.JarVerifier.getSystemEntropy(JarVerifier.java:785)
at javax.crypto.JarVerifier.testSignatures(JarVerifier.java:706)
at javax.crypto.JarVerifier.access$400(JarVerifier.java:34)
at javax.crypto.JarVerifier$1.run(JarVerifier.java:183)
at javax.crypto.JarVerifier$1.run(JarVerifier.java:149)
at java.security.AccessController.doPrivileged(Native Method)
at javax.crypto.JarVerifier.<clinit>(JarVerifier.java:148)
at javax.crypto.JceSecurity.loadPolicies(JceSecurity.java:316)
at javax.crypto.JceSecurity.setupJurisdictionPolicies(JceSecurity.java:261)
at javax.crypto.JceSecurity.access$000(JceSecurity.java:48)
at javax.crypto.JceSecurity$1.run(JceSecurity.java:81)
at java.security.AccessController.doPrivileged(Native Method)
at javax.crypto.JceSecurity.<clinit>(JceSecurity.java:78)
at javax.crypto.SecretKeyFactory.getInstance(SecretKeyFactory.java:204)
at TestProviderLeak.main(TestProviderLeak.java:98)