Increase default max stack size (facebook#923)

Summary:
As discussed in facebook#135, the default stack size doesn't work for all use cases. In particular, when very large and complex bundles are loaded in dev mode.

This PR bumps the default stack size from `64*1024` (512kB) to `128*1024` (1MB). As suggested by tmikov in this comment - facebook#135 (comment).

Pull Request resolved: facebook#923

Reviewed By: tmikov

Differential Revision: D43630032

Pulled By: neildhar

fbshipit-source-id: 5f8cff91a5f01b6507870c61efa1ce507de67940

public/hermes/Public/RuntimeConfig.h

@@ -35,7 +35,7 @@ class PinnedHermesValue;
   F(constexpr, PinnedHermesValue *, RegisterStack, nullptr)            \
                                                                        \
   /* Register Stack Size */                                            \
-  F(constexpr, unsigned, MaxNumRegisters, 64 * 1024)                   \
+  F(constexpr, unsigned, MaxNumRegisters, 128 * 1024)                  \
                                                                        \
   /* Whether or not the JIT is enabled */                              \
   F(constexpr, bool, EnableJIT, false)                                 \