less clones and more cleanup for rustc_builtin_macros

[cyrgani]

Currently based on #161867, blocked on that PR being merged.

[panstromek]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 73366f0 (73366f0da15ddcf8000af24409c8c343bb5c092c)
Base parent: 4fcf397 (4fcf39725a9c99bd495d8c73af83628a256ff9a9)

[rust-timer]

Finished benchmarking commit (73366f0): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never rustc-perf
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.4%	[-1.0%, -0.2%]	7
All ❌✅ (primary)	0.2%	[0.2%, 0.2%]	3

Max RSS (memory usage)

Results (primary 1.2%, secondary 4.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.2%	[1.2%, 1.2%]	1
Regressions ❌ (secondary)	4.4%	[4.4%, 4.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.2%	[1.2%, 1.2%]	1

Cycles

Results (primary -3.7%, secondary -3.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.7%	[-4.6%, -2.9%]	2
Improvements ✅ (secondary)	-3.8%	[-3.8%, -3.8%]	1
All ❌✅ (primary)	-3.7%	[-4.6%, -2.9%]	2

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 476.065s -> 474.054s (-0.42%)
Artifact size: 401.18 MiB -> 400.93 MiB (-0.06%)