Add reset_dynbal_baselines to a test

We want at least one restart test that covers the new
reset_dynbal_baselines flag, to make sure restarts happen properly with
this flag: the baselines set in the initial run should be preserved
across restart.

Also, change this test from ERS to ERP to catch errors related to
changing processor count.

cime_config/testdefs/testlist_clm.xml

@@ -761,13 +761,13 @@
       <option name="wallclock">00:20:00</option>
     </options>
   </test>
-  <test name="ERS_D_Ld10" grid="f10_f10_musgs" compset="IHistClm50SpG" testmods="clm/glcMEC_decrease">
+  <test name="ERP_P36x2_D_Ld10" grid="f10_f10_musgs" compset="IHistClm50SpG" testmods="clm/glcMEC_decrease">
     <machines>
       <machine name="cheyenne" compiler="intel" category="aux_clm"/>
     </machines>
     <options>
       <option name="wallclock">00:20:00</option>
-      <option name="comment"  >test transient PFTs (via HIST) in conjunction with changing glacier area</option>
+      <option name="comment"  >Test transient PFTs (via HIST) in conjunction with changing glacier area. This test also covers the reset_dynbal_baselines option. CISM is not answer preserving across processor changes, but short test length should be OK.</option>
     </options>
   </test>
   <test name="ERS_D_Ld10" grid="f10_f10_musgs" compset="IHistClm50Sp" testmods="clm/collapse_pfts_78_to_16_decStart_f10">

cime_config/testdefs/testmods_dirs/clm/glcMEC_decrease/user_nl_clm

@@ -1 +1,7 @@
 for_testing_allow_non_annual_changes = .true.
+
+! Also test the reset_dynbal_baselines flag. We want at least one restart test that uses
+! this flag; for this test to have power, it should have some change in glacier area
+! after the restart. (So, in this decrease test, the glacier decrease should be slow
+! enough that there is some decrease after the restart.)
+reset_dynbal_baselines = .true.