RFR (S) 8231769: Test tools/javac/tree/MakeTypeTest.java fails with -Xcheck:jni

[coleen.phillimore at oracle.com]

Summary: Delete local jni handles in 
create_from_platform_dependent_str() after upcall to Java.

The JVM_GetProperties function was creating many local refs which are 
never cleaned up, hence overflowing the EnsureLocalCapacity call.

Tested with tier1 -Xcheck:jni locally and tier2-3.

open webrev at http://cr.openjdk.java.net/~coleenp/2019/8231769.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8231769

Thanks,
Coleen