[Client]Allow to override PULSAR_MEM settings via PULSAR_EXTRA_OPS (#13381)
[Client]Allow to override PULSAR_MEM settings via PULSAR_EXTRA_OPS (#13381)

### Motivation

`pulsar-client` runs `conf/pulsar_tools_env.sh` to set `PULSAR_EXTRA_OPTS`. If `PULSAR_EXTRA_OPTS` are given in the command line and contain `-Xmx`, it will be overridden by `PULSAR_MEM`.

### Modifications

Exchange the order of applying env variables. First go the hardcoded PULSAR_MEM settings, then potentially the user settings.
massakam/pulsar,massakam/pulsar,merlimat/pulsar,yahoo/pulsar,massakam/pulsar,yahoo/pulsar,merlimat/pulsar,yahoo/pulsar,merlimat/pulsar,yahoo/pulsar,merlimat/pulsar,massakam/pulsar,yahoo/pulsar,merlimat/pulsar,massakam/pulsar,massakam/pulsar,yahoo/pulsar,merlimat/pulsar