Speed up type checking by caching argument inference context (#19323)

This speeds up self check by about 1.5% on my computer, according to
`perf_compare.py`:
```
...
=== Results ===

master                    4.264s (0.0%) | stdev 0.024s 
HEAD                      4.201s (-1.5%) | stdev 0.030s 
```
I noticed this bottleneck when I was looking at a CPU profile generated
using the script from #19322.

Author: JukkaL

mypy/checkexpr.py

@@ -318,6 +318,8 @@ class ExpressionChecker(ExpressionVisitor[Type], ExpressionCheckerSharedApi):
     strfrm_checker: StringFormatterChecker
     plugin: Plugin
 
+    _arg_infer_context_cache: ArgumentInferContext | None
+
     def __init__(
         self,
         chk: mypy.checker.TypeChecker,
@@ -352,6 +354,8 @@ def __init__(
         self.is_callee = False
         type_state.infer_polymorphic = not self.chk.options.old_type_inference
 
+        self._arg_infer_context_cache = None
+
     def reset(self) -> None:
         self.resolved_type = {}
 
@@ -2277,9 +2281,11 @@ def infer_function_type_arguments_pass2(
         return callee_type, inferred_args
 
     def argument_infer_context(self) -> ArgumentInferContext:
-        return ArgumentInferContext(
-            self.chk.named_type("typing.Mapping"), self.chk.named_type("typing.Iterable")
-        )
+        if self._arg_infer_context_cache is None:
+            self._arg_infer_context_cache = ArgumentInferContext(
+                self.chk.named_type("typing.Mapping"), self.chk.named_type("typing.Iterable")
+            )
+        return self._arg_infer_context_cache
 
     def get_arg_infer_passes(
         self,