[flang][acc] Add infrastructure and tests for ACCImplicitData (#166797)

This PR adds the necessary infrastructure to enable testing of the
ACCImplicitData pass for FIR/HLFIR, along with comprehensive test
coverage for implicit data clause generation in OpenACC constructs.

New Infrastructure:
- Add FIROpenACCSupport analysis providing FIR-specific implementations
of OpenACCSupport interface methods for variable name extraction, recipe
name generation, and NYI emission
- Add FIROpenACCUtils with helper functions for:
  * Variable name extraction from FIR operations (getVariableName)
  * Recipe name generation with FIR type string representation
  * Bounds checking for constant array sections
- Add ACCInitializeFIRAnalyses pass to pre-register FIR analyses
(OpenACCSupport and AliasAnalysis) for use by subsequent OpenACC passes
in the pipeline

Refactoring in flang/lib/Lower/OpenACC.cpp:
- Move bounds string generation and bounds checking to FIROpenACCUtils
- Refactor recipe name generation to use fir::acc::getRecipeName

Test Coverage:
- acc-implicit-firstprivate.fir: Tests implicit firstprivate behavior
for scalar types (i8, i16, i32, i64, f32, f64, logical, complex) in
parallel/serial constructs with recipe generation verification
- acc-implicit-data.fir: Tests implicit data clauses for scalars,
arrays, derived types, and boxes in kernels/parallel/serial with
default(none) and default(present) variations
- acc-implicit-data-fortran.F90: Fortran tests verifying implicit data
generation through bbc with both HLFIR and FIR
- acc-implicit-data-derived-type-member.F90: Tests correct ordering of
parent/child data clause operations for derived type members
- acc-implicit-copy-reduction.fir: Tests enable-implicit-reduction-copy
flag controlling whether reduction variables use copy or firstprivate

This enables proper testing of implicit data clause generation through
the flang optimizer pipeline for OpenACC directives.