FindEnvMod: Remove unreliable test case

There's no way to know that loading an arbitrary module doesn't pull in
extra dependent modules so the test case asserting that exactly one module
was loaded isn't valid.

Tests/FindEnvModules/EnvModules.cmake

@@ -18,18 +18,16 @@ if(avail_mods)
 
   message("module list")
   env_module_list(loaded_mods)
+  set(mod0_found FALSE)
   foreach(mod IN LISTS loaded_mods)
     message("  ${mod}")
+    if(NOT mod0_found AND mod MATCHES "^${mod0}")
+      set(mod0_found ${mod})
+    endif()
   endforeach()
 
-  list(LENGTH loaded_mods num_loaded_mods)
-  message("Number of modules loaded: ${num_loaded_mods}")
-  if(NOT num_loaded_mods EQUAL 1)
-    message(FATAL_ERROR "Exactly 1 module should be loaded.  Found ${num_loaded_mods}")
-  endif()
-
-  list(GET loaded_mods 0 mod0_actual)
-  if(NOT (mod0_actual MATCHES "^${mod0}"))
-    message(FATAL_ERROR "Loaded module does not match ${mod0}.  Actual: ${mod0_actual}")
+  if(NOT mod0_found)
+    message(FATAL_ERROR "Requested module ${mod0} not found in loaded modules")
   endif()
+  message("module ${mod0} found loaded as ${mod0_found}")
 endif()