libbinder_ndk: avoid need to allocate heap status

Only allocate this once globally, since it is expected to be used on
almost every NDK-backend binder transaction.

Fixes: 167686803
Test: CtsNdkBinderTestCases
Change-Id: I1d2c5ca05a1ee6ceb5b41966e441aa51c1c315af
2 files changed