Rollup merge of rust-lang#45108 - phil-opp:patch-2, r=japaric

Fix data-layout field in x86_64-unknown-linux-gnu.json test file

The current data-layout causes the following error:

> rustc: /checkout/src/llvm/lib/CodeGen/MachineFunction.cpp:151: void llvm::MachineFunction::init(): Assertion `Target.isCompatibleDataLayout(getDataLayout()) && "Can't create a MachineFunction using a Module with a " "Target-incompatible DataLayout attached\n"' failed.

The new value was generated according to [this comment by @japaric](rust-lang#31367 (comment)).

src/test/run-make/target-specs/Makefile

@@ -5,5 +5,5 @@ all:
 	$(RUSTC) foo.rs --target=my-invalid-platform.json 2>&1 | grep -q "Error loading target specification"
 	$(RUSTC) foo.rs --target=my-incomplete-platform.json 2>&1 | grep 'Field llvm-target'
 	RUST_TARGET_PATH=. $(RUSTC) foo.rs --target=my-awesome-platform --crate-type=lib --emit=asm
-	RUST_TARGET_PATH=. $(RUSTC) foo.rs --target=x86_64-unknown-linux-gnu --crate-type=lib --emit=asm
+	RUST_TARGET_PATH=. $(RUSTC) foo.rs --target=my-x86_64-unknown-linux-gnu-platform --crate-type=lib --emit=asm
 	$(RUSTC) -Z unstable-options --target=my-awesome-platform.json --print target-spec-json > $(TMPDIR)/test-platform.json && $(RUSTC) -Z unstable-options --target=$(TMPDIR)/test-platform.json --print target-spec-json | diff -q $(TMPDIR)/test-platform.json -

src/test/run-make/target-specs/x86_64-unknown-linux-gnu.json → src/test/run-make/target-specs/my-x86_64-unknown-linux-gnu-platform.json

@@ -1,6 +1,6 @@
 {
     "pre-link-args": ["-m64"],
-    "data-layout": "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128",
+    "data-layout": "e-m:e-i64:64-f80:128-n8:16:32:64-S128",
     "linker-flavor": "gcc",
     "llvm-target": "x86_64-unknown-linux-gnu",
     "target-endian": "little",