[core] Remove re-linking programs approach (#14482)

Remove re-linking programs as redundant.
It costs (cheaper to link once than twice) and (subjective) is not that common GL API
usage pattern, although perfectly legal and permitted.
Initial idea, behind the removed code, was to enable work on optimization
that would reduce number of attrib setup calls in case when VAO is not
available (as described in #9433).

As such optimization is not implemented, and it is arguable if it makes sense
to do it now, we can remove re-linking.

Related to closed PRs #9433 and PR #11583.

I have [measured the time spent just on relinking](https://gist.github.com/astojilj/29bd5a5c5dc0b2d9f29ecb660da07fbf) using release build on iPhone SE (A9, same as iPhone 6S):

- 1st run after reboot or installation
Total 37.14ms, average per program:1.86ms

- reopening
Total: 2.47ms, average per program: 0.12ms

This time we save using the patch here.

1 files changed, 3 insertions, 8 deletions

diff --git a/src/mbgl/gl/program.hpp b/src/mbgl/gl/program.hpp
index 3757c442de..8540385e97 100644
--- a/src/mbgl/gl/program.hpp
+++ b/src/mbgl/gl/program.hpp
@@ -49,15 +49,10 @@ public:
                  const std::initializer_list<const char*>& fragmentSource)
             : program(context.createProgram(
                   context.createShader(ShaderType::Vertex, vertexSource),
-                  context.createShader(ShaderType::Fragment, fragmentSource))),
-              attributeLocations(context, program) {
-            // Re-link program after manually binding only active attributes in Attributes::queryLocations
-            context.linkProgram(program);
-
-            // We have to re-initialize the uniforms state from the bindings as the uniform locations
-            // get shifted on some implementations
+                  context.createShader(ShaderType::Fragment, fragmentSource),
+                  attributeLocations.getFirstAttribName())) {
+            attributeLocations.queryLocations(program);
             uniformStates.queryLocations(program);
-
             // Texture units are specified via uniforms as well, so we need query their locations
             textureStates.queryLocations(program);
         }