Update multiview state on program executable change

Relinking the active program can change its number of views and the
state has to be correspondingly adjusted.

BUG=angleproject:2062
TEST=angle_end2end_tests

Change-Id: I20102a428d7566a8cec5d81eeaa55980665812f4
Reviewed-on: https://chromium-review.googlesource.com/637994
Commit-Queue: Martin Radev <mradev@nvidia.com>
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index 137b7c1..c7ec67c 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -4603,6 +4603,7 @@
     Program *programObject = getProgram(program);
     ASSERT(programObject);
     handleError(programObject->link(this));
+    mGLState.onProgramExecutableChange(programObject);
 }
 
 void Context::releaseShaderCompiler()