HPCC-9078 The default system will not start on a 32-bit VM with 10 GB RAM

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>

This change prevent to crash Thor component on a 32 bit environment when
more than 2 GB physical RAM exits.

Originally the condition was more than 4GB, but in 32 bit OS environment
only 3 GB or less memory can use by application.

This change improves the Roxie memory allocation error handling (it used by Thor heap allocation too). Beyond the pure error code value this change logging human readable error explanation, too.