LibGL: Make `glDeleteTextures` skip over 0 names

As stated in the manual:
     glDeleteTextures silently ignores 0's and names that do not
     correspond to existing textures.

If we do not skip these 0 names, they end up as invalid free texture
names in our name allocator.

Userland/Libraries/LibGL/SoftwareGLContext.cpp

@@ -673,10 +673,12 @@ void SoftwareGLContext::gl_delete_textures(GLsizei n, const GLuint* textures)
     RETURN_WITH_ERROR_IF(n < 0, GL_INVALID_VALUE);
     RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
 
-    m_name_allocator.free(n, textures);
-
     for (auto i = 0; i < n; i++) {
         GLuint name = textures[i];
+        if (name == 0)
+            continue;
+
+        m_name_allocator.free(name);
 
         auto texture_object = m_allocated_textures.find(name);
         if (texture_object == m_allocated_textures.end() || texture_object->value.is_null())

Userland/Libraries/LibGL/Tex/NameAllocator.cpp

@@ -22,12 +22,9 @@ void TextureNameAllocator::allocate(GLsizei count, GLuint* textures)
     }
 }
 
-void TextureNameAllocator::free(GLsizei count, const GLuint* textures)
+void TextureNameAllocator::free(GLuint texture)
 {
-    size_t tex_array_index = 0;
-
-    while (count-- > 0)
-        m_free_texture_names.push(textures[tex_array_index++]);
+    m_free_texture_names.push(texture);
 }
 
 }

Userland/Libraries/LibGL/Tex/NameAllocator.h

@@ -16,7 +16,7 @@ public:
     TextureNameAllocator() = default;
 
     void allocate(GLsizei count, GLuint* textures);
-    void free(GLsizei count, const GLuint* textures);
+    void free(GLuint texture);
 
 private:
     Stack<GLuint, 512> m_free_texture_names;