Make _matfun and tr GPU tests version-aware

- _matfun: only return Hermitian on Julia 1.12+ where Julia itself does
- tr GPU tests: @gpu_broken only on Julia 1.12+ (scalar indexing issue),
  @gpu on older versions where it works

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: claude

src/rulesets/LinearAlgebra/symmetric.jl

@@ -386,7 +386,8 @@ function _matfun(f, A::LinearAlgebra.RealHermSymComplexHerm)
     elseif eltype(fλ) <: Complex
         # Complex input with complex output: plain Matrix
         fA
-    elseif A isa Hermitian
+    elseif A isa Hermitian && VERSION >= v"1.12.0-DEV.0"
+        # Julia 1.12+ returns Hermitian for Hermitian input with real output
         Hermitian(fA)
     else
         Symmetric(fA)

test/rulesets/LinearAlgebra/dense.jl

@@ -138,9 +138,14 @@
         test_rrule(logabsdet, -B)
     end
     @testset "tr" begin
-        # tr uses scalar indexing in LinearAlgebra, broken on GPU arrays
-        @gpu_broken test_frule(tr, randn(4, 4))
-        @gpu_broken test_rrule(tr, randn(4, 4))
+        if VERSION >= v"1.12.0-DEV.0"
+            # tr uses scalar indexing in LinearAlgebra on Julia 1.12+, broken on GPU arrays
+            @gpu_broken test_frule(tr, randn(4, 4))
+            @gpu_broken test_rrule(tr, randn(4, 4))
+        else
+            @gpu test_frule(tr, randn(4, 4))
+            @gpu test_rrule(tr, randn(4, 4))
+        end
     end
     @testset "sylvester" begin
         @testset "T=$T, m=$m, n=$n" for T in (Float64, ComplexF64), m in (2, 3), n in (1, 3)