Enable passing e2e tests for ROCM, VMVX, and Vulkan backends

[hanhanW]

Enable tests that were previously excluded but now pass:

ROCM/HIP (tests/e2e/linalg):

• conv2d, narrow_n_matmuls, subbyte_to_fp, fp_to_subbyte, fp4_f32_conversion, index

VMVX (tests/e2e/linalg):

• argmax, index

VMVX (tests/e2e/linalg_ext_ops):

• attention

Vulkan (tests/e2e/linalg):

• argmax, index

Vulkan (tests/e2e/linalg_ext_ops):

• map_gather, map_scatter, top-k

Vulkan (tests/e2e/stablehlo_ops):

• reverse

Below is the additional testing time on my machine (using gfx1100):

● Test execution times for newly enabled tests:
  ┌──────────┬───────┬────────────┐
  │ Backend  │ Tests │ Total Time │
  ├──────────┼───────┼────────────┤
  │ ROCM/HIP │ 6     │ 3.06 sec   │
  ├──────────┼───────┼────────────┤
  │ VMVX     │ 3     │ 0.28 sec   │
  ├──────────┼───────┼────────────┤
  │ Vulkan   │ 6     │ 0.58 sec   │
  ├──────────┼───────┼────────────┤
  │ Total    │ 15    │ ~3.9 sec   │
  └──────────┴───────┴────────────┘
  Individual test breakdown:

  ROCM/HIP:
  - conv2d: 0.28s
  - fp4_f32_conversion: 0.39s
  - fp_to_subbyte: 0.43s
  - index: 0.27s
  - narrow_n_matmuls: 0.97s
  - subbyte_to_fp: 0.72s

  VMVX:
  - argmax: 0.04s
  - index: 0.04s
  - attention: 0.20s

  Vulkan:
  - argmax: 0.05s
  - index: 0.05s
  - map_gather: 0.13s
  - map_scatter: 0.12s
  - top-k: 0.19s
  - reverse: 0.05s

  All tests are fast (under 1 second each). The slowest is narrow_n_matmuls on ROCM at ~1 second.