Start handling stack depth issues in explorer (#2799)

Adds stack space handling similar to Clang's approach, but with more support for forwarding return values. Refactors ParseAndExecute for better sharing, and for centralization of the InitStackSpace handling.

Fixes #2795

explorer/parse_and_execute/parse_and_execute_test.cpp

@@ -0,0 +1,42 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "explorer/parse_and_execute/parse_and_execute.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+namespace Carbon::Testing {
+namespace {
+
+using ::testing::Eq;
+
+TEST(ParseAndExecuteTest, Recursion) {
+  std::string source = R"(
+    package Test api;
+    fn Main() -> i32 {
+      return
+  )";
+  // A high depth that's expected to complete in a few seconds.
+  static constexpr int Depth = 50000;
+  for (int i = 0; i < Depth; ++i) {
+    source += "if true then\n";
+  }
+  source += "1\n";
+  for (int i = 0; i < Depth; ++i) {
+    source += "else 0\n";
+  }
+  source += R"(
+        ;
+    }
+  )";
+  auto err = ParseAndExecute("explorer/data/prelude.carbon", source);
+  ASSERT_FALSE(err.ok());
+  EXPECT_THAT(err.error().message(),
+              Eq("RUNTIME ERROR: overflow:1: stack overflow: too many "
+                 "interpreter actions on stack"));
+}
+
+}  // namespace
+}  // namespace Carbon::Testing