7069863: G1: SIGSEGV running SPECjbb2011 and -UseBiasedLocking Summary: Align the reserved size of the heap and perm to the heap region size to get a preferred heap base that is aligned to the region size, and call the correct heap reservation constructor. Also add a check in the heap reservation code that the reserved space starts at the requested address (if any). Reviewed-by: kvn, ysr