Added a new test_env.txt file to capture common shell variable. Added concept of COMPILEJAVA for use when TESTJAVA is a JRE. If COMPILEJAVA not set then TESTJAVA will be the default with assumption it is a JDK.
Reviewed-by: kvn, brutisso, coleenp
7123945: runtime/6878713/Test6878713.sh require about 2G of native memory, swaps and times out
Add new diagnostic option -XX:MallocMaxTestWords=NNN and fix Test6878713.sh.
Reviewed-by: dcubed, coleenp, dholmes, iklam
