[lldb] Turn lldb_private::Status into a value type. (#106163)

This patch removes all of the Set.* methods from Status.

This cleanup is part of a series of patches that make it harder use the
anti-pattern of keeping a long-lives Status object around and updating
it while dropping any errors it contains on the floor.

This patch is largely NFC, the more interesting next steps this enables
is to:
1. remove Status.Clear()
2. assert that Status::operator=() never overwrites an error
3. remove Status::operator=()

Note that step (2) will bring 90% of the benefits for users, and step
(3) will dramatically clean up the error handling code in various
places. In the end my goal is to convert all APIs that are of the form

`    ResultTy DoFoo(Status& error)
`
to

`    llvm::Expected<ResultTy> DoFoo()
`
How to read this patch?

The interesting changes are in Status.h and Status.cpp, all other
changes are mostly

` perl -pi -e 's/\.SetErrorString/ = Status::FromErrorString/g' $(git
grep -l SetErrorString lldb/source)
`
plus the occasional manual cleanup.

1 files changed, 10 insertions, 5 deletions

diff --git a/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp b/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp
index 5087540..8e7386d 100644
--- a/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp
+++ b/lldb/source/Breakpoint/BreakpointResolverFileLine.cpp
@@ -46,14 +46,16 @@ BreakpointResolverSP BreakpointResolverFileLine::CreateFromStructuredData(
   success = options_dict.GetValueForKeyAsString(GetKey(OptionNames::FileName),
                                                 filename);
   if (!success) {
-    error.SetErrorString("BRFL::CFSD: Couldn't find filename entry.");
+    error =
+        Status::FromErrorString("BRFL::CFSD: Couldn't find filename entry.");
     return nullptr;
   }
 
   success = options_dict.GetValueForKeyAsInteger(
       GetKey(OptionNames::LineNumber), line);
   if (!success) {
-    error.SetErrorString("BRFL::CFSD: Couldn't find line number entry.");
+    error =
+        Status::FromErrorString("BRFL::CFSD: Couldn't find line number entry.");
     return nullptr;
   }
 
@@ -67,21 +69,24 @@ BreakpointResolverSP BreakpointResolverFileLine::CreateFromStructuredData(
   success = options_dict.GetValueForKeyAsBoolean(GetKey(OptionNames::Inlines),
                                                  check_inlines);
   if (!success) {
-    error.SetErrorString("BRFL::CFSD: Couldn't find check inlines entry.");
+    error = Status::FromErrorString(
+        "BRFL::CFSD: Couldn't find check inlines entry.");
     return nullptr;
   }
 
   success = options_dict.GetValueForKeyAsBoolean(
       GetKey(OptionNames::SkipPrologue), skip_prologue);
   if (!success) {
-    error.SetErrorString("BRFL::CFSD: Couldn't find skip prologue entry.");
+    error = Status::FromErrorString(
+        "BRFL::CFSD: Couldn't find skip prologue entry.");
     return nullptr;
   }
 
   success = options_dict.GetValueForKeyAsBoolean(
       GetKey(OptionNames::ExactMatch), exact_match);
   if (!success) {
-    error.SetErrorString("BRFL::CFSD: Couldn't find exact match entry.");
+    error =
+        Status::FromErrorString("BRFL::CFSD: Couldn't find exact match entry.");
     return nullptr;
   }