GDB settings not honored per debug session

Type: Debugger

Describe the bug
OS and Version: Debian 9 x86_64
VS Code Version: 1.39.2
C/C++ Extension Version: 0.26.0
GDB Version: 8.3.1

To Reproduce
Create a simple hello world program and two distinct debug configurations, both of which target the same executable. Launch both sessions concurrently where in session 1 you issue -exec set auto-solib-add off and in the other you issue -exec set auto-solib-add on. Note that depending on the order in which you issue these commands, the other session will have its value overwritten.

Expected behavior
Both debug sessions should honor their solib-add settings. Session 1 should not automatically load shared library debug symbols despite such setting being overwritten in Session 2. It seems both sessions currently use the same MIEngine.