Add tests for function call inout passing style

Author: filipsajdak

regression-tests/pure2-inout-passing-style-call.cpp2

@@ -0,0 +1,8 @@
+f2: (inout x) -> _ = {
+    return x * 2;
+}
+
+main: () -> int = {
+    x := 21;
+    std::cout << f2(inout x) << std::endl;
+}

regression-tests/test-results/apple-clang-14/pure2-inout-passing-style-call.cpp.execution

@@ -0,0 +1 @@
+42

regression-tests/test-results/apple-clang-14/pure2-inout-passing-style-call.cpp.output

@@ -0,0 +1 @@
+42

regression-tests/test-results/clang-12/pure2-inout-passing-style-call.cpp.execution

@@ -0,0 +1,23 @@
+
+#define CPP2_USE_MODULES         Yes
+
+#include "cpp2util.h"
+
+
+#line 1 "pure2-inout-passing-style-call.cpp2"
+[[nodiscard]] auto f2(auto& x) -> auto;
+#line 5 "pure2-inout-passing-style-call.cpp2"
+[[nodiscard]] auto main() -> int;
+
+//=== Cpp2 definitions ==========================================================
+
+#line 1 "pure2-inout-passing-style-call.cpp2"
+[[nodiscard]] auto f2(auto& x) -> auto{
+    return x * 2; 
+}
+
+[[nodiscard]] auto main() -> int{
+    auto x {21}; 
+    std::cout << f2(      x) << std::endl;
+}
+

regression-tests/test-results/clang-12/pure2-inout-passing-style-call.cpp.output

@@ -0,0 +1,8 @@
+f2: (inout x) -> _ = {
+    return x * 2;
+}
+
+main: () -> int = {
+    x := 21;
+    std::cout << f2(inout x) << std::endl;
+}

regression-tests/test-results/pure2-inout-passing-style-call.cpp

@@ -0,0 +1,2 @@
+pure2-inout-passing-style-call.cpp2... ok (all Cpp2, passes safety checks)
+