test_common: fix -Wformat warnings

In preparation of re-enabling -Wformat globally, fix format string
warnings in test_common.

Printing a `size_t` requires the `%zu` specifier.

Signed-off-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

test_common/gl/helpers.cpp

@@ -1047,8 +1047,10 @@ void * CreateGLTexture2DMultisample( size_t width, size_t height, size_t samples
  GLint max_samples = get_gl_max_samples(target, internalFormat);
  check_gl_error()
 
- if (max_samples < (GLint)samples)
- log_error("GL error: requested samples (%d) exceeds renderer max samples (%d)\n", samples, max_samples);
+ if (max_samples < (GLint)samples)
+ log_error("GL error: requested samples (%zu) exceeds renderer max "
+ "samples (%d)\n",
+ samples, max_samples);
 
  // Setup the GLSL program
  const GLchar *vertex_source =
@@ -1145,7 +1147,9 @@ void * CreateGLTexture2DMultisample( size_t width, size_t height, size_t samples
  check_gl_error();
 
  if (fbo_samples < (GLint)samples)
- log_error("GL Error: requested samples (%d) exceeds FBO capability (%d)\n", samples, fbo_samples);
+ log_error(
+ "GL Error: requested samples (%zu) exceeds FBO capability (%d)\n",
+ samples, fbo_samples);
 
  glUseProgram(prog);
  check_gl_error()
@@ -1306,7 +1310,9 @@ void * CreateGLTexture2DArrayMultisample(size_t width, size_t height,
  GLint max_samples = get_gl_max_samples(target, internalFormat);
 
  if (max_samples < (GLint)samples)
- log_error("GL error: requested samples (%d) exceeds renderer max samples (%d)\n", samples, max_samples);
+ log_error("GL error: requested samples (%zu) exceeds renderer max "
+ "samples (%d)\n",
+ samples, max_samples);
 
  // Setup the GLSL program
  const GLchar *vertex_source =
@@ -1438,7 +1444,9 @@ void * CreateGLTexture2DArrayMultisample(size_t width, size_t height,
  check_gl_error();
 
  if (fbo_samples < (GLint)samples)
- log_error("GL Error: requested samples (%d) exceeds FBO capability (%d)\n", samples, fbo_samples);
+ log_error(
+ "GL Error: requested samples (%zu) exceeds FBO capability (%d)\n",
+ samples, fbo_samples);
 
  glUseProgram(prog);
  check_gl_error()