also take back the rest of the rand bump

Author: RalfJung

alloc_miri_test/Cargo.toml

@@ -16,8 +16,8 @@ default = ["miri-test-libstd"]
 miri-test-libstd = []
 
 [dev-dependencies]
-rand = "0.8"
-rand_xorshift = "0.3"
+rand = "0.7"
+rand_xorshift = "0.2"
 # This lets tests access the `core` and `alloc` crates.
 core = { path = "../fake/core" }
 alloc = { path = "../fake/alloc" }

core_miri_test/Cargo.toml

@@ -23,7 +23,6 @@ name = "coretests"
 path = "../library/core/tests/lib.rs"
 
 [dev-dependencies]
-rand = "0.8"
-rand_xorshift = "0.3"
+rand = "0.7"
 # This lets tests access the `core` crate.
 core = { path = "../fake/core" }

std_miri_test/Cargo.toml

@@ -26,8 +26,7 @@ std_detect = { path = "../fake/std_detect" }
 rustc-demangle = { path = "../fake/rustc-demangle" }
 
 [dev-dependencies]
-rand = "0.8"
-rand_xorshift = "0.3"
+rand = "0.7"
 
 [features]
 # Empty this crate