JIT: fix double reporting of some failures in the inline tree

[AndyAyersMS]

We now eagerly create inlinee contexts when we try and inline, so in post-inline debug when we go to scan the trees for the calls that remain, we need to remember which ones were failed inline candidates and which ones we were never inline candidates.

[Copilot]

Pull Request Overview

This PR fixes a bug in the JIT compiler where some inline failures were being double-reported in debug builds. The fix adds tracking to distinguish between calls that were considered for inlining but failed versus calls that were never inline candidates.

Key changes:

• Adds a new debug flag to track failed inline candidates
• Updates inline failure handling to mark calls that were attempted but failed
• Modifies post-inline debug scanning to avoid double-reporting

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/coreclr/jit/gentree.h	Adds GTF_CALL_MD_WAS_CANDIDATE flag and accessor methods for tracking failed inline candidates
src/coreclr/jit/fginline.cpp	Sets the new flag on inline failures and updates debug scanning logic to check for it

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[AndyAyersMS]

For a simple test case

#using System.Runtime.CompilerServices;

X.Test();

class X
{
    static int sum()
    {
        int sum = 0;

        for (int i = 0; i < 100; i++)
        {
            sum += i;
        }

        return sum;
    }

    [MethodImpl(MethodImplOptions.NoInlining)]
    static int bar() => 3;

    [MethodImpl(MethodImplOptions.NoInlining)]
    public static int Test()
    {
        return sum() + bar() + sum();
    }
}

and with a checked build and

set DOTNET_JitPrintInlinedMethods=X:Test
set DOTNET_JitPrintInlinedMethodsVerbose=1
set DOTNET_TieredCompilation=0

we used to print

Inlines into X:Test():int:
  [FAILED: unprofitable inline] X:sum():int
  [FAILED: unprofitable inline] X:sum():int
  [FAILED: noinline per IL/cached result] X:bar():int
  [FAILED: unprofitable inline] X:sum():int
  [FAILED: unprofitable inline] X:sum():int

and now print

Inlines into X:Test():int:
  [FAILED: unprofitable inline] X:sum():int
  [FAILED: noinline per IL/cached result] X:bar():int
  [FAILED: unprofitable inline] X:sum():int

@dotnet/jit-contrib PTAL

Debug only change; no diffs.

[AndyAyersMS]

/ba-g host activation tests failed but no log to match on in one case