folly: fix github ci tests on macos arm

Summary:
These were [failing on github](https://github.com/facebook/folly/actions/runs/9923539774/job/27413784309#step:48:6919)

I think the problem was the macos runner changed from intel to arm, expectations needed updating for arm.

X-link: facebook/folly#2253

Reviewed By: ndmitchell

Differential Revision: D59733599

Pulled By: ahornby

fbshipit-source-id: e7f00184e867a5bf296836ea8c4a4f2430d9635a

third-party/folly/src/folly/memory/test/ArenaTest.cpp

@@ -77,6 +77,10 @@ TEST(Arena, SizeSanity) {
   minimum_size += 10 * requestedBlockSize;
   maximum_size +=
       goodMallocSize(10 * requestedBlockSize + SysArena::kBlockOverhead);
+#if defined(__APPLE__) && defined(FOLLY_AARCH64)
+  // expectation is a bit too small
+  maximum_size += 8;
+#endif
   EXPECT_GE(arena.totalSize(), minimum_size);
   EXPECT_LE(arena.totalSize(), maximum_size);
   VLOG(4) << minimum_size << " < " << arena.totalSize() << " < "

third-party/folly/src/folly/test/ConstexprMathTest.cpp

@@ -987,7 +987,13 @@ TEST_F(ConstexprMathTest, constexpr_exp_floating) {
   }
   {
     constexpr auto a = folly::constexpr_exp(471.L);
+#if defined(__APPLE__) && defined(FOLLY_AARCH64)
+    EXPECT_LT( // too inexact for expect-double-eq
+        std::exp(471.L) / a - 1,
+        16 * lim::epsilon());
+#else
     EXPECT_DOUBLE_EQ(std::exp(471.L), a);
+#endif
   }
   {
     constexpr auto a = folly::constexpr_exp(600.);