Rollup merge of #73142 - ehuss:std-benches, r=dtolnay

Ensure std benchmarks get tested.

This ensures that the std benchmarks don't break in the future. Currently they aren't compiled or tested on CI, so they can easily bitrot.  Testing a benchmark runs it with one iteration. Adding these should only add a few seconds to CI.

Closes #54176
Closes #61913

Author: RalfJung

src/liballoc/Cargo.toml

@@ -25,6 +25,7 @@ path = "../liballoc/tests/lib.rs"
 [[bench]]
 name = "collectionsbenches"
 path = "../liballoc/benches/lib.rs"
+test = true
 
 [[bench]]
 name = "vec_deque_append_bench"

src/libcore/Cargo.toml

@@ -19,6 +19,7 @@ path = "../libcore/tests/lib.rs"
 [[bench]]
 name = "corebenches"
 path = "../libcore/benches/lib.rs"
+test = true
 
 [dev-dependencies]
 rand = "0.7"

src/libcore/benches/lib.rs

@@ -1,3 +1,5 @@
+// wasm32 does not support benches (no time).
+#![cfg(not(target_arch = "wasm32"))]
 #![feature(flt2dec)]
 #![feature(test)]
 

src/libstd/Cargo.toml

@@ -74,3 +74,8 @@ std_detect_dlsym_getauxval = []
 threads = 125
 # Maximum heap size
 heap_size = 0x8000000
+
+[[bench]]
+name = "stdbenches"
+path = "benches/lib.rs"
+test = true