ES31: Add PROGRAM_SEPARABLE to ProgramParameter and GetProgram

BUG=angleproject:1939
TEST=angle_end2end_tests

Change-Id: I97ad11360f7c015947a2c0cc7d4a47f994726834
Reviewed-on: https://chromium-review.googlesource.com/454264
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index a5d52e0..02f7c83 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -2340,10 +2340,7 @@
 void Context::programParameteri(GLuint program, GLenum pname, GLint value)
 {
     gl::Program *programObject = getProgram(program);
-    ASSERT(programObject != nullptr);
-
-    ASSERT(pname == GL_PROGRAM_BINARY_RETRIEVABLE_HINT);
-    programObject->setBinaryRetrievableHint(value != GL_FALSE);
+    SetProgramParameteri(programObject, pname, value);
 }
 
 void Context::initRendererString()