test: Change LoadContext() return value type from int to bool

It should be then consistent with SDL_SetError().

test/testgles2.c

@@ -70,7 +70,7 @@ static bool suspend_when_occluded;
 static GLES2_Context ctx;
 static shader_data *datas;
 
-static int LoadContext(GLES2_Context *data)
+static bool LoadContext(GLES2_Context *data)
 {
 #ifdef SDL_VIDEO_DRIVER_UIKIT
 #define __SDL_NOGETPROCADDR__
@@ -92,7 +92,7 @@ static int LoadContext(GLES2_Context *data)
 
 #include "../src/render/opengles2/SDL_gles2funcs.h"
 #undef SDL_PROC
-    return 0;
+    return true;
 }
 
 /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
@@ -764,7 +764,7 @@ int main(int argc, char *argv[])
     }
 
     /* Important: call this *after* creating the context */
-    if (LoadContext(&ctx) < 0) {
+    if (!LoadContext(&ctx)) {
         SDL_Log("Could not load GLES2 functions\n");
         quit(2);
         return 0;