[compiler-rt][lit] initialize LIT LLVMConfig instance

to handle lit tools searching. Otherwise
compiler-rt depends on system environment variable PATH for lit tools
which diverge from the other LLVM projects. This reverts D83486 which
really should be implemented in LIT itself when the PATH is constructed.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D122837

compiler-rt/test/lit.common.cfg.py

@@ -172,8 +172,6 @@ if config.asan_shadow_scale != '':
 if config.memprof_shadow_scale != '':
   config.target_cflags += " -mllvm -memprof-mapping-scale=" + config.memprof_shadow_scale
 
-config.environment = dict(os.environ)
-
 # Clear some environment variables that might affect Clang.
 possibly_dangerous_env_vars = ['ASAN_OPTIONS', 'DFSAN_OPTIONS', 'HWASAN_OPTIONS',
                                'LSAN_OPTIONS', 'MSAN_OPTIONS', 'UBSAN_OPTIONS',

compiler-rt/test/lit.common.configured.in

@@ -18,6 +18,7 @@ set_default("compiler_rt_src_root", "@COMPILER_RT_SOURCE_DIR@")
 set_default("compiler_rt_obj_root", "@COMPILER_RT_BINARY_DIR@")
 set_default("enable_per_target_runtime_dir", @LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_PYBOOL@)
 set_default("llvm_tools_dir", "@LLVM_TOOLS_DIR@")
+set_default("lit_tools_dir", "@LLVM_LIT_TOOLS_DIR@")
 set_default("llvm_shlib_dir", "@LLVM_LIBRARY_OUTPUT_INTDIR@")
 set_default("gnu_ld_executable", "@GNU_LD_EXECUTABLE@")
 set_default("gold_executable", "@GOLD_EXECUTABLE@")
@@ -76,5 +77,8 @@ config.compiler_rt_libdir = lit_config.substitute(config.compiler_rt_libdir)
 if not os.path.exists(config.clang):
   lit_config.fatal("Can't find compiler on path %r" % config.clang)
 
+import lit.llvm
+lit.llvm.initialize(lit_config, config)
+
 # Setup attributes common for all compiler-rt projects.
 lit_config.load_config(config, "@COMPILER_RT_SOURCE_DIR@/test/lit.common.cfg.py")