NoSuchMethodException: sun.misc.IOUtils.readAllBytes on java 8

Works with jdk 10 and jdk 14, but not java 8
```
java -jar BumbleBench.jar StringEqualsBench
Exception in thread "main" java.lang.ExceptionInInitializerError
Caused by: java.lang.RuntimeException: java.lang.NoSuchMethodException: sun.misc.IOUtils.readAllBytes(java.io.InputStream)
at net.adoptopenjdk.bumblebench.core.Util.(Util.java:44)
Caused by: java.lang.NoSuchMethodException: sun.misc.IOUtils.readAllBytes(java.io.InputStream)
at java.lang.Class.getDeclaredMethod(Class.java:2130)
at net.adoptopenjdk.bumblebench.core.Util.(Util.java:36)
```
java version
```
openjdk version "1.8.0_222"
OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_222-b10)
OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.222-b10, mixed mode)
```

Start with Util.java at the stack-trace locations around lines 36 and 44, then run java -jar BumbleBench.jar StringEqualsBench on the reported OpenJDK 8 version. Done means the StringEqualsBench command starts without the NoSuchMethodException while preserving compatibility with the newer JDK versions mentioned.

Written by the indexing model from the issue text.