[lldb/crashlog] Fix frame parser regex for when there is no source info

[mib]

Summary

It can happen that the originator of a crash report doesn't have access
to certain images. When that's the case, ReportCrash won't show the
source info in the crash report stack frames, but only the stack address
and image name.

This patch fixes a bug in the crashlog stackframe parser regular
expression to optionally match the source info group.

rdar://101934135

Signed-off-by: Med Ismail Bennani <[e-mail]>

lldb/examples/python/crashlog.py

class TextCrashLogParser(CrashLogParser):
     thread_instrs_regex = re.compile(r'^Thread \d+ instruction stream')
     thread_regex = re.compile(r'^Thread (\d+).*:')
     app_backtrace_regex = re.compile(r'^Application Specific Backtrace (\d+).*:')
     version = r'\(.+\)|(?:arm|x86_)[0-9a-z]+'
     frame_regex = re.compile(r'^(\d+)\s+'              # id
                              r'(.+?)\s+'               # img_name
                              r'(?:' +version+ r'\s+)?' # img_version
                              r'(0x[0-9a-fA-F]{4,})'    # addr (4 chars or more)
-                             r' +(.*)'                 # offs
+                             r'(?: +(.*))?'            # offs
                             )
     null_frame_regex = re.compile(r'^\d+\s+\?\?\?\s+0{4,} +')
     image_regex_uuid = re.compile(r'(0x[0-9a-fA-F]+)'          # img_lo
                                   r'\s+-\s+'                   #   -
                                   r'(0x[0-9a-fA-F]+)\s+'       # img_hi
                                   r'[+]?(.+?)\s+'              # img_name
                                   r'(?:(' +version+ r')\s+)?'  # img_version
                                   r'(?:<([-0-9a-fA-F]+)>\s+)?' # img_uuid

lldb/test/Shell/ScriptInterpreter/Python/Crashlog/Inputs/a.out.crash

 Exception Note:        EXC_CORPSE_NOTIFY
 
 Termination Signal:    Segmentation fault: 11
 Termination Reason:    Namespace SIGNAL, Code 0xb
 Terminating Process:   exc handler [21606]
 
 Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
 0   a.out                           @foo@ foo + 16 (test.c:3)
-1   a.out                           @bar@ bar + 9 (test.c:6)
+1   a.out                           @bar@
 2   a.out                           @main@ main + 20 (test.c:8)
 3   libdyld.dylib                   0x1000000 start + 1
 
 Thread 0 crashed with X86 Thread State (64-bit):
   rax: 0x0000000000000000  rbx: 0x0000000000000000  rcx: 0x00007ffee42d81d0  rdx: 0x00007ffee42d8080
   rdi: 0x0000000000000001  rsi: 0x00007ffee42d8070  rbp: 0x00007ffee42d8020  rsp: 0x00007ffee42d8020
    r8: 0x0000000000000000   r9: 0x0000000000000000  r10: 0x0000000000000000  r11: 0x0000000000000000
   r12: 0x0000000000000000  r13: 0x0000000000000000  r14: 0x0000000000000000  r15: 0x0000000000000000