This PR lets users provide --debug-only flags with python decorators.
This greatly simplifies the debugging experience in python.

Co-authored-by: Tres <tpopp@users.noreply.github.com>

Reverts llvm/llvm-project#146297 because #131837 is reverted in #146850

PR145731 corrected the analyzer test runner to consider use of z3 when
used by testcases, which exposed problems in test cases PR37855.c and
crashes in z3-crosscheck.c This change fixes those crashes and
re-enables the test cases that were "XFAIL"'d out.

Co-authored-by: einvbri <vince.a.bridgers@ericsson.com>

This patch is part of a series that adds origin-tracking to the debugify
source location coverage checks, allowing us to report symbolized stack
traces of the point where missing source locations appear.

This patch adds the logic for collecting stack traces in DebugLoc
instances. We do not symbolize the stack traces in this patch - that
only happens when we decide to actually print them, which will be the
responsibility of debugify. The collection happens in the constructor of
a DebugLoc that has neither a valid location nor an annotation; we also
collect an extra stack trace every time we call setDebugLoc, as
sometimes the more interesting point is not where the DebugLoc was
constructed, but where it was applied to an instruction. This takes the
form of a getCopied() method on DebugLoc, which is the identity function
in normal builds, but adds an extra stack trace in origin-tracking
builds.

It must be "REQUIRES:", "REQUIRES :" does not actually check
the requirement.

The target is called "x86" not "x86_64".

Two problems here:
* Missing ":" after REQUIRES, so it was never checked for
  and ran anyway.
* The target name is "x86" not "x86_64".

Nested AddRec is already rejected by the handling in pushSCEV().

Add abbreviations for icmp/fcmp, store and br, which are the most common
instructions that don't have abbreviations yet. This requires increasing
the abbreviation size to 5 bits.

This gives about 3-5% bitcode size reductions for the clang build.