[debuginfo-tests] Fix environment variable used to specify LLDB

Currently, if the user specifies the environment variable 'CLANG', tests
will attempt to use the value as a path to the clang executable.
Previously, lldb could also be specified via the CLANG environment
variable, but this was almost certainly a bug, because that meant both
clang and lldb would have the same path. This patch changes the
environment variable for lldb to 'LLDB'.

Reviewed by: thopre, teemperor

Differential Revision: https://reviews.llvm.org/D101982

Author: jh7370

debuginfo-tests/lit.cfg.py

@@ -118,7 +118,7 @@ def can_target_host():
         'debuginfo-tests project.'.format(config.host_triple))
 
 # Check which debuggers are available:
-built_lldb = llvm_config.use_llvm_tool('lldb', search_env='CLANG')
+built_lldb = llvm_config.use_llvm_tool('lldb', search_env='LLDB')
 lldb_path = None
 if built_lldb is not None:
     lldb_path = built_lldb

llvm/utils/lit/lit/TestingConfig.py

@@ -22,12 +22,13 @@ def fromdefaults(litConfig):
             }
 
         pass_vars = ['LIBRARY_PATH', 'LD_LIBRARY_PATH', 'SYSTEMROOT', 'TERM',
-                     'CLANG', 'LD_PRELOAD', 'ASAN_OPTIONS', 'UBSAN_OPTIONS',
-                     'LSAN_OPTIONS', 'ADB', 'ANDROID_SERIAL', 'SSH_AUTH_SOCK',
-                     'SANITIZER_IGNORE_CVE_2016_2143', 'TMPDIR', 'TMP', 'TEMP',
-                     'TEMPDIR', 'AVRLIT_BOARD', 'AVRLIT_PORT',
-                     'FILECHECK_OPTS', 'VCINSTALLDIR', 'VCToolsinstallDir',
-                     'VSINSTALLDIR', 'WindowsSdkDir', 'WindowsSDKLibVersion']
+                     'CLANG', 'LLDB', 'LD_PRELOAD', 'ASAN_OPTIONS',
+                     'UBSAN_OPTIONS', 'LSAN_OPTIONS', 'ADB', 'ANDROID_SERIAL',
+                     'SSH_AUTH_SOCK', 'SANITIZER_IGNORE_CVE_2016_2143',
+                     'TMPDIR', 'TMP', 'TEMP', 'TEMPDIR', 'AVRLIT_BOARD',
+                     'AVRLIT_PORT', 'FILECHECK_OPTS', 'VCINSTALLDIR',
+                     'VCToolsinstallDir', 'VSINSTALLDIR', 'WindowsSdkDir',
+                     'WindowsSDKLibVersion']
 
         if sys.platform == 'win32':
             pass_vars.append('INCLUDE')