Revert "Defer source path remap tilde expansion until source file use"

This reverts commit c274b6e5.

The x86_64 debian bot got a failure with this patch,
https://lab.llvm.org/buildbot#builders/68/builds/33078
where
SymbolFile/DWARF/x86/DW_TAG_variable-DW_AT_decl_file-DW_AT_abstract_origin-crosscu1.s
is crashing here -

 #2 0x0000000000425a9f SignalHandler(int) Signals.cpp:0:0
 #3 0x00007f57160e9140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14140)
 #4 0x00007f570d911e43 lldb_private::SourceManager::GetFile(lldb_private::FileSpec const&) crtstuff.c:0:0
 #5 0x00007f570d914270 lldb_private::SourceManager::DisplaySourceLinesWithLineNumbers(lldb_private::FileSpec const&, unsigned int, unsigned int, unsigned int, unsigned int, char const*, lldb_private::Stream*, lldb_private::SymbolContextList const*) crtstuff.c:0:0
 #6 0x00007f570da662c8 lldb_private::StackFrame::GetStatus(lldb_private::Stream&, bool, bool, bool, char const*) crtstuff.c:0:0

I don't get a failure here my mac, I'll review this method more
closely tomorrow.