[cmake] Make gtest include directories a part of the library interface

This applies the same fix that D84748 did for macro definitions.
Appropriate include path is now automatically set for all libraries
which link against gtest targets, which avoids the need to set
include_directories in various parts of the project.

Differential Revision: https://reviews.llvm.org/D86616

GitOrigin-RevId: 9cb222e749e8392517a138cf6645a7c220d671c8
1 file changed