RFR: 8149778: serviceability/tmtools/jstat/GcCapacityTest.java causes JVM to hang during GC

[Robbin Ehn]

Hi all,

In 8152989 "-Xmx128M" was added to this test.
This seem to solves timeout issues (describe by Kim in case).

So this patch removes the ignore flag from test.

It also address the issue raised by Kim by looping over long instead of float.

Bug: https://bugs.openjdk.java.net/browse/JDK-8149778
Webrev: http://cr.openjdk.java.net/~rehn/8149778/webrev/

Tested on multiple platforms and hosts.

Thanks!

/Robbin