[15] RFR(S) 8240538: [JVMCI] add test for JVMCI ConstantPool class

[Vladimir Kozlov]

This JVMCI test was ported by Doug S. from GraalVM.

https://cr.openjdk.java.net/~kvn/8240538/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8240538

Tested with hs-tier1 which runs JVMCI tests.

Thanks,
Vladimir