Clearly reject files too short to be ELF files.

Bug: 11597000

(cherry picked from commit bf92c35fa82b3ebb8be8cf489a0be40415914a74)

Change-Id: I85c14aeeff6e8855f303108b099be12ef6b87a16
diff --git a/tests/src/android/os/cts/ReadElf.java b/tests/src/android/os/cts/ReadElf.java
index b43fd36..b4041d2 100644
--- a/tests/src/android/os/cts/ReadElf.java
+++ b/tests/src/android/os/cts/ReadElf.java
@@ -252,8 +252,11 @@
         mPath = file.getPath();
         mFile = new RandomAccessFile(file, "r");
 
-        readIdent();
+        if (mFile.length() < EI_NIDENT) {
+            throw new IllegalArgumentException("Too small to be an ELF file: " + file);
+        }
 
+        readIdent();
         readHeader();
     }