Some Imperas configuration changes to match unimplemented Wally registers

config/rv64gc/imperas.ic

@@ -57,6 +57,17 @@
 #--override cpu/instret_undefined=T
 #--override cpu/hpmcounter_undefined=T
 
+--override cpu/scontext_undefined=T
+--override cpu/mcontext_undefined=T
+--override cpu/mnoise_undefined=T
+# *** how to override other undefined registers: seed, mphmevent, mseccfg, debugger registers
+#--override cpu/seed_undefined=T
+#--override mhpmevent3_undefined=T
+#--override cpu/mseccfg_undefined=T
+#--override cpu/tselect_undefined=T
+#--override cpu/tdata1_undefined=T
+
+
 --override cpu/reset_address=0x80000000
 
 --override cpu/unaligned=T  # Zicclsm (should be true)