CLN: revisit build warnings in cython templates (#27346)

Author: pilkibun

pandas/_libs/groupby_helper.pxi.in

@@ -76,7 +76,11 @@ def group_last_{{name}}({{c_type}}[:, :] out,
                 val = values[i, j]
 
                 # not nan
-                if val == val and val != {{nan_val}}:
+                if (
+                {{if not name.startswith("int")}}
+                val == val and
+                {{endif}}
+                val != {{nan_val}}):
                     nobs[lab, j] += 1
                     resx[lab, j] = val
 
@@ -133,7 +137,11 @@ def group_nth_{{name}}({{c_type}}[:, :] out,
                 val = values[i, j]
 
                 # not nan
-                if val == val and val != {{nan_val}}:
+                if (
+                {{if not name.startswith("int")}}
+                val == val and
+                {{endif}}
+                val != {{nan_val}}):
                     nobs[lab, j] += 1
                     if nobs[lab, j] == rank:
                         resx[lab, j] = val

pandas/_libs/hashtable_class_helper.pxi.in

@@ -424,8 +424,12 @@ cdef class {{name}}HashTable(HashTable):
             for i in range(n):
                 val = values[i]
 
-                if ignore_na and (val != val
-                                  or (use_na_value and val == na_value2)):
+                if ignore_na and (
+                {{if not name.lower().startswith(("uint", "int"))}}
+                val != val or
+                {{endif}}
+                (use_na_value and val == na_value2)
+                ):
                     # if missing values do not count as unique values (i.e. if
                     # ignore_na is True), skip the hashtable entry for them,
                     # and replace the corresponding label with na_sentinel