Fix deprecation warnings in test suite

Remove test code that called deprecated linear indexing APIs without
@test_deprecated wrappers, causing warnings in CI output:

- interface_tests.jl: Remove lastindex(va) test without dimension arg
  (already covered by lastindex(va, 2) test on preceding lines)
- copy_static_array_test.jl: Replace a_voa[i] with a_voa.u[i]

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: claude

test/copy_static_array_test.jl

@@ -90,8 +90,8 @@ b_voa = copy(a_voa)
 a_voa[:, 1] = SVector(1.0)
 a_voa[:, 2] = SVector(1.0)
 @. b_voa = a_voa
-@test b_voa[:, 1] == a_voa[1]
-@test b_voa[:, 2] == a_voa[2]
+@test b_voa[:, 1] == a_voa.u[1]
+@test b_voa[:, 2] == a_voa.u[2]
 
 a = [SVector(0.0) for _ in 1:2]
 a_voa = VectorOfArray(a)

test/interface_tests.jl

@@ -73,10 +73,6 @@ last_col = lastindex(testva_end, 2)
 @inferred testva_end[1, last_col]
 @inferred testva_end[1, 1:last_col]
 @test testva_end[1, last_col] == 2.0
-last_col = lastindex(testva_end)
-@inferred testva_end[1, last_col]
-@inferred testva_end[1, 1:last_col]
-@test testva_end[1, last_col] == 2.0
 last_row = lastindex(testva_end, 1)
 @inferred testva_end[last_row, 1]
 @inferred testva_end[1:last_row, 1]