contracts: Update to Polkavm 0.5 (#2945)

This will allow us to change to the target supporting atomics and makes
the linker file no longer necessary.

Cargo.lock

@@ -3294,7 +3294,7 @@ dependencies = [
  "gimli 0.27.3",
  "hashbrown 0.13.2",
  "log",
- "regalloc2",
+ "regalloc2 0.6.1",
  "smallvec",
  "target-lexicon",
 ]
@@ -13793,6 +13793,12 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fecd2caacfc4a7ee34243758dd7348859e6dec73f5e5df059890f5742ee46f0e"
 
+[[package]]
+name = "polkavm-common"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88b4e215c80fe876147f3d58158d5dfeae7dabdd6047e175af77095b78d0035c"
+
 [[package]]
 name = "polkavm-derive"
 version = "0.4.0"
@@ -13809,7 +13815,7 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c99f4e7a9ff434ef9c885b874c99d824c3a5693bf5e3e8569bb1d2245a8c1b7f"
 dependencies = [
- "polkavm-common",
+ "polkavm-common 0.4.0",
  "proc-macro2",
  "quote",
  "syn 2.0.48",
@@ -13817,15 +13823,16 @@ dependencies = [
 
 [[package]]
 name = "polkavm-linker"
-version = "0.4.0"
+version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "550738c1b49b9279fa19d8ebed81f551b911b869227a20a190f85f6db45d5d0e"
+checksum = "a5a668bb33c7f0b5f4ca91adb1e1e71cf4930fef5e6909f46c2180d65cce37d0"
 dependencies = [
  "gimli 0.28.0",
  "hashbrown 0.14.3",
  "log",
  "object 0.32.2",
- "polkavm-common",
+ "polkavm-common 0.5.0",
+ "regalloc2 0.9.3",
  "rustc-demangle",
 ]
 
@@ -14597,6 +14604,19 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "regalloc2"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad156d539c879b7a24a363a2016d77961786e71f48f2e2fc8302a92abd2429a6"
+dependencies = [
+ "hashbrown 0.13.2",
+ "log",
+ "rustc-hash",
+ "slice-group-by",
+ "smallvec",
+]
+
 [[package]]
 name = "regex"
 version = "1.10.2"