7143858: G1: Back to back young GCs with the second GC having a minimally sized eden Summary: Before the last thread to leave a JNI critical region was able to schedule a GCLocker Initiated GC, another thread was attempting an allocation and saw that the GCLocker region was no longer active and successfully scheduled a GC. Stall allocating threads until the GCLocker Initiated GC is performed and then retry the allocation. Reviewed-by: brutisso, huntch

os_family = linux

arch = x86

arch_model = x86_32

os_arch = linux_x86

os_arch_model = linux_x86_32

lib_arch = i386

compiler = sparcWorks

gnu_dis_arch = i386

sysdefs = -DLINUX -DSPARC_WORKS -D_GNU_SOURCE -DIA32