Increase the allocation limit again.

Still getting a few flakes, so double the allowed tries.

Bug: 128872105

Test: Test passes.
Change-Id: I0fb3d74655eaece6660dec26a2a1d01430ef8fbc
diff --git a/libc/bionic/malloc_limit.cpp b/libc/bionic/malloc_limit.cpp
index 69a8f89..b42865b 100644
--- a/libc/bionic/malloc_limit.cpp
+++ b/libc/bionic/malloc_limit.cpp
@@ -275,7 +275,7 @@
   // being called, allow up to five ms for the signal handler to complete
   // before failing.
   bool enabled = false;
-  size_t num_tries = 10;
+  size_t num_tries = 20;
   while (true) {
     if (!atomic_exchange(&gGlobalsMutating, true)) {
       __libc_globals.mutate([](libc_globals* globals) {