[lldb] Explicitly open file to write with utf-8 encoding in crashlog.py

The python "open" function will use the default encoding for the
locale (the result of "locale.getpreferredencoding()"). Explicitly set
the locale to utf-8 when opening the crashlog for writing, as there may
be non-ascii symbols in there (for example, Swift uses "τ" to indicate
generic parameters).

rdar://101402755

Differential Revision: https://reviews.llvm.org/D136798

Author: augusto2112

lldb/examples/python/crashlog.py

@@ -568,7 +568,7 @@ def parse_json(buffer):
                 head, _, tail = buffer.partition("\n")
                 return json.loads(tail)
 
-        with open(path, "r") as f:
+        with open(path, "r", encoding="utf-8") as f:
             buffer = f.read()
         try:
             return parse_json(buffer)
@@ -910,7 +910,7 @@ def __init__(self, debugger, path, options):
         self.symbols = {}
 
     def parse(self):
-        with open(self.path, "r") as f:
+        with open(self.path, "r", encoding="utf-8") as f:
             lines = f.read().splitlines()
 
         idx = 0
@@ -1257,7 +1257,7 @@ def save_crashlog(debugger, command, exe_ctx, result, dict):
             "error: invalid arguments, a single output file is the only valid argument"
         )
         return
-    out_file = open(args[0], "w")
+    out_file = open(args[0], "w", encoding="utf-8")
     if not out_file:
         result.PutCString("error: failed to open file '%s' for writing...", args[0])
         return