Feature/mrhs misc

[maddyscientist]

This PR is a bit of a catch all

• Adds register talking for MRHS staggered dslash
  • Level of register tiling is controlled by a CMake parameter QUDA_MAX_MULTI_RHS_TILE, with the default left at size 1 for now.
  • This feature will be further developed in subsequent PRs
  • (Although not included in this PR, it's straightforward to this support to other stencils)
• Update to the latest version of Eigen on the 3.4 branch
  • This has improved support for nvc++ allowing us to remove some prior WARs
• Fixes performance regressions of the MMA dslash when the memory pool is switched off
  • The FieldTmp now supports creating temporaries using parameters as opposed another field instance
  • We use this to create the temporary used for the reordered quark fields
• Adds WAR for performance regressions with ROCm
  • This improves performance on ROCm 5.3 by 30% for the Laplace 3-d operator, though it's still off by integer factors
• Various fixes for nvc++ compilation
• Add alternative sentinel for heterogeneous reductions in the case that the compiler optimizes away non-finite math (enabled with QUDA_HETEROGENEOUS_ATOMIC_INF_INIT=OFF). Not a problem by default, but is with latest clang with -Ofast.
• Fix various compiler warnings with more recent compilers, e.g., gcc-15
• Fixes a hang caused by process divergence when calling printGenericMatrix

[weinbe2]

Pending a few cosmetic requests this looks good. Thanks @maddyscientist !