Add pe layout for G compset with MARBL and WW3

Use the same layout as G compset with WW3 but not MARBL, except I bump
NTASKS_OCN up to 2560.

I also fixed a bug where G compset with MARBL and SWAV was letting 2304 cores
sit idle (ROOTPE_OCN was 2560 instead of 256)

Author: mnlevy1981

cime_config/config_pes.xml

@@ -171,7 +171,7 @@
           <rootpe_rof>0</rootpe_rof>
           <rootpe_cpl>0</rootpe_cpl>
           <rootpe_ice>128</rootpe_ice>
-          <rootpe_ocn>2560</rootpe_ocn>
+          <rootpe_ocn>256</rootpe_ocn>
           <rootpe_lnd>0</rootpe_lnd>
           <rootpe_wav>0</rootpe_wav>
           <rootpe_glc>0</rootpe_glc>
@@ -210,6 +210,39 @@
           <rootpe_glc>0</rootpe_glc>
         </rootpe>
       </pes>
+      <pes pesize="any" compset="_DATM.+_CICE.*_MOM6%[^_]*MARBL-BIO.+_WW3">
+        <comment>none</comment>
+        <ntasks>
+          <ntasks_atm>128</ntasks_atm>
+          <ntasks_rof>128</ntasks_rof>
+          <ntasks_cpl>128</ntasks_cpl>
+          <ntasks_ice>128</ntasks_ice>
+          <ntasks_ocn>2560</ntasks_ocn>
+          <ntasks_lnd>1</ntasks_lnd>
+          <ntasks_wav>256</ntasks_wav>
+          <ntasks_glc>1</ntasks_glc>
+        </ntasks>
+        <nthrds>
+          <nthrds_atm>1</nthrds_atm>
+          <nthrds_lnd>1</nthrds_lnd>
+          <nthrds_rof>1</nthrds_rof>
+          <nthrds_ice>1</nthrds_ice>
+          <nthrds_ocn>1</nthrds_ocn>
+          <nthrds_glc>1</nthrds_glc>
+          <nthrds_wav>1</nthrds_wav>
+          <nthrds_cpl>1</nthrds_cpl>
+        </nthrds>
+        <rootpe>
+          <rootpe_atm>0</rootpe_atm>
+          <rootpe_rof>0</rootpe_rof>
+          <rootpe_cpl>0</rootpe_cpl>
+          <rootpe_ice>0</rootpe_ice>
+          <rootpe_ocn>384</rootpe_ocn>
+          <rootpe_lnd>0</rootpe_lnd>
+          <rootpe_wav>128</rootpe_wav>
+          <rootpe_glc>0</rootpe_glc>
+        </rootpe>
+      </pes>
       <pes pesize="any" compset="_DATM.+_DICE.*_MOM6(?!.*%MARBL-BIO).+_SWAV">
         <comment>none</comment>
         <ntasks>