StackFrame::getFileName implementation incorrectly assumes that native methods do not have source file.

Trivial fix.

diff --git a/src/java.base/share/classes/java/lang/StackFrameInfo.java b/src/java.base/share/classes/java/lang/StackFrameInfo.java
--- a/src/java.base/share/classes/java/lang/StackFrameInfo.java
+++ b/src/java.base/share/classes/java/lang/StackFrameInfo.java
@@ -87,9 +87,6 @@
 
     @Override
     public String getFileName() {
- if (isNativeMethod())
- return null;
-
         return toStackTraceElement().getFileName();
     }