[flang] Disable trampoline test for PPC (NFC) (#187194)

flang-rt/test/Driver/safe-trampoline-gnustack.f90

@@ -1,6 +1,7 @@
 ! UNSUPPORTED: system-windows
 ! UNSUPPORTED: offload-cuda
 ! UNSUPPORTED: system-darwin
+! UNSUPPORTED: target=powerpc{{.*}}
 
 ! Verify that -fsafe-trampoline produces an executable whose
 ! GNU_STACK program header is RW (not RWE), proving W^X compliance.

flang-rt/test/lit.site.cfg.py.in

@@ -11,6 +11,7 @@ config.flang_rt_experimental_offload_support = "@FLANG_RT_EXPERIMENTAL_OFFLOAD_S
 config.cc = "@CMAKE_C_COMPILER@"
 config.flang = "@CMAKE_Fortran_COMPILER@"
 config.osx_sysroot = path(r"@CMAKE_OSX_SYSROOT@")
+config.target_triple = "@LLVM_TARGET_TRIPLE@"
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)