RFR: 8283422: Create a new test for JDK-8254790

[Sergey Bylokhov]

The [JDK-8254790](https://bugs.openjdk.java.net/browse/JDK-8254790) initially was reported on macOS.
It was found by the "javax/xml/crypto/dsig/GenerationTests.java" test which for some reason worked fine on Linux/Windows most? of the time.

I tried to run that test on Linux/Windows many times on a few systems and it always pass. Also, I got the same result for the tier1...tier4 tests.

I have found that the easiest way to reproduce the crash is to pass the result of the string.indexOf to the str.charAt when the heap is big enough. The test below[1] trigger the crash 1000 time in a row on win/lin on systems I have tested.

I am not sure what is the best way to contribute to the test, should I create a stand-alone test like[1], or update an existing test as I did for the first version of this PR?

[1]:

package compiler.intrinsics.string;

import static jdk.test.lib.Asserts.assertTrue;

public final class TestStringIndexOfLargeHeap {
    static final int[] data = new int[Integer.MAX_VALUE / 2];
    public static void main(String[] args) throws Exception {
        test('a');
        test('\ubeef');
    }
    private static void test(char ch) {
        String str = ("0123456789" + ch).repeat(100);
        for (int i = 0; i < 1_000_000; ++i) {
            assertTrue(ch == str.charAt(str.indexOf(ch)));
        }
    }
}

-------------

Commit messages:
 - Add vm.bits == "64"
 - Initial version

Changes: https://git.openjdk.java.net/jdk/pull/7883/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7883&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283422
  Stats: 42 lines in 1 file changed: 40 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7883.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7883/head:pull/7883

PR: https://git.openjdk.java.net/jdk/pull/7883