Simplify iterator usage (#15185)

This PR fixes the
[`FURB129`](https://github.com/dosisod/refurb/blob/master/docs/checks.md#furb129-simplify-readlines),
and
[`FURB130`](https://github.com/dosisod/refurb/blob/master/docs/checks.md#furb130-no-in-dict-keys)
error codes in [Refurb](https://github.com/dosisod/refurb).

See #14887

Author: dosisod

mypy/main.py

@@ -1498,7 +1498,7 @@ def read_types_packages_to_install(cache_dir: str, after_run: bool) -> list[str]
         # No missing stubs.
         return []
     with open(fnam) as f:
-        return [line.strip() for line in f.readlines()]
+        return [line.strip() for line in f]
 
 
 def install_types(

mypy/stubtest.py

@@ -1667,7 +1667,7 @@ def strip_comments(s: str) -> str:
             return s.strip()
 
     with open(allowlist_file) as f:
-        for line in f.readlines():
+        for line in f:
             entry = strip_comments(line)
             if entry:
                 yield entry

mypyc/irbuild/expression.py

@@ -812,10 +812,10 @@ def transform_basic_comparison(
     if (
         is_int_rprimitive(left.type)
         and is_int_rprimitive(right.type)
-        and op in int_comparison_op_mapping.keys()
+        and op in int_comparison_op_mapping
     ):
         return builder.compare_tagged(left, right, op, line)
-    if is_fixed_width_rtype(left.type) and op in int_comparison_op_mapping.keys():
+    if is_fixed_width_rtype(left.type) and op in int_comparison_op_mapping:
         if right.type == left.type:
             op_id = ComparisonOp.signed_ops[op]
             return builder.builder.comparison_op(left, right, op_id, line)
@@ -826,7 +826,7 @@ def transform_basic_comparison(
             )
     elif (
         is_fixed_width_rtype(right.type)
-        and op in int_comparison_op_mapping.keys()
+        and op in int_comparison_op_mapping
         and isinstance(left, Integer)
     ):
         op_id = ComparisonOp.signed_ops[op]