EGL_BAD_SURFACE returned when using MapView.onDestroy() with multiple mapviews

[zugaldia]

Looks like that when having multiple Map Views with a Custom Layer a race condition might occur that causes an EGL_BAD_SURFACE error.

For example, let's suppose two maps are present, one in the background and another one as a dialog. When the dialog map shows up fine and gets destroyed, "active" count inside native_map_view.cpp will stay 0 or 1, but when a custom layer is added, sometimes it will go over to 3, so when the control is released back, the original NativeMap will never take control again.

the 07-05 17:18:15.778 29086 29086 I mbgl    : {t.android.debug}[Android]: Trying to activate -1111333760, 0
07-05 17:18:15.778 29086 29086 I mbgl    : {t.android.debug}[Android]: Activated -1111333760
07-05 17:18:15.787 29086 29086 I mbgl    : {t.android.debug}[Android]: Trying to deactivate -1111333760, 1
07-05 17:18:15.787 29086 29086 I mbgl    : {t.android.debug}[Android]: Deactivated -1111333760
07-05 17:18:15.791 29086 29086 I mbgl    : {t.android.debug}[Android]: Trying to activate -1111333760, 0
07-05 17:18:15.791 29086 29086 I mbgl    : {t.android.debug}[Android]: Activated -1111333760
07-05 17:18:15.791 29086 29086 I mbgl    : {t.android.debug}[General]: New custom layer Impl: my_map
07-05 17:18:15.791 29086 29086 I mbgl    : {t.android.debug}[General]: New custom layer: my_map
07-05 17:18:15.792 29086 29086 I mbgl    : {t.android.debug}[Android]: Trying to activate -1111333760, 1
07-05 17:18:15.792 29086 29894 D nyc_MapRenderingLayer: Map rendering prepare has been called.
07-05 17:18:15.792 29086 29086 I mbgl    : {t.android.debug}[Android]: Trying to activate -1111333760, 2
07-05 17:18:15.792 29086 29894 D nyc_MapRenderingLayer: Layers added above sc-layers-insert
07-05 17:18:15.793 29086 29086 I mbgl    : {t.android.debug}[Android]: Trying to deactivate -1111333760, 3

cc: @kkaefer @tobrun

[tobrun]

This was fixed and cherry picked with #9538