Update binary build matrix for release 2.14

The 2.14 branch cut is done, so the test channel now serves 2.14.0 release
candidates. Applies the standard post-branch-cut update to `main`, matching
what `.github/workflows/release-pytorch-post-branch-cut.yml` does:

1. `CURRENT_CANDIDATE_VERSION` 2.13.0 -> 2.14.0 (= `CURRENT_NIGHTLY_VERSION`).
   For the test channel `initialize_globals()` sets
   `CURRENT_VERSION = CURRENT_CANDIDATE_VERSION`, surfaced as `stable_version`
   and enforced by `smoke_test.py`. Left at 2.13.0 it fails with
   `Torch version mismatch, expected 2.13.0 for channel test`.

2. Sync the test channel with nightly in `CUDA_ARCHES_DICT` (adds 13.4) and
   `ROCM_ARCHES_DICT` (7.1, 7.2 -> 7.2, 7.14). These match what release/2.14
   actually builds, so without them 2.14 RC validation would skip the cu134
   and rocm7.14 wheels and try to validate rocm7.1 wheels that aren't
   produced. `PYTHON_ARCHES_DICT` already matched nightly.

`CURRENT_STABLE_VERSION` stays 2.13.0 (current GA); it moves separately when
2.14 goes live. The release channel matrix is unchanged.

Test plan:
- `python -m tools.tests.test_generate_binary_build_matrix` - 11 tests pass.
- `--update-reference-files` produces no asset changes.
- Generated linux wheel matrix, before -> after:
  - test: `stable_version` 2.13.0 -> 2.14.0, cuda +cu134, rocm 7.1 -> 7.14
  - release: unchanged (2.13.0, cu126/130/132, rocm7.1/7.2)
  - nightly: unchanged

Authored with the assistance of Claude Code.

Author: atalman

tools/scripts/generate_binary_build_matrix.py

@@ -45,13 +45,13 @@
 }
 CUDA_ARCHES_DICT = {
     "nightly": ["12.6", "13.0", "13.2", "13.4"],
-    "test": ["12.6", "13.0", "13.2"],
+    "test": ["12.6", "13.0", "13.2", "13.4"],
     "release": ["12.6", "13.0", "13.2"],
 }
 
 ROCM_ARCHES_DICT = {
     "nightly": ["7.2", "7.14"],
-    "test": ["7.1", "7.2"],
+    "test": ["7.2", "7.14"],
     "release": ["7.1", "7.2"],
 }
 
@@ -99,7 +99,7 @@
 
 
 CURRENT_NIGHTLY_VERSION = "2.14.0"
-CURRENT_CANDIDATE_VERSION = "2.13.0"
+CURRENT_CANDIDATE_VERSION = "2.14.0"
 CURRENT_STABLE_VERSION = "2.13.0"
 CURRENT_VERSION = CURRENT_STABLE_VERSION